To your final point I will again say that this is not a table top RPG, it's not a pen and paper RPG, it's a computer RPG, a video game, it's going to take time to kill enemies, you aren't just rolling a dice and the outcome is set, that's random luck, not skill and almost all gamers want skill involved so no, we don't need a 'kill-all-enemies button'. As I said at the beginning, you are just going to have to accept that the genre has evolved along with the technology and you're going to get a very different experience than you got with BG2. However the game will most likely ship with difficulty levels and like DOS2 (and other games) have a story mode where fights are so easy they're over much faster.
The problem is not about difficulty at all. When I play a fantasy adventure I want to play sword and socery and not pit shoving and barrelmancy.
For me the current combat system is utterly without soul and fun. It is a silly puzzle solving game paired with spamming of the same spell/action again and again.
I wouldn't care if they threw the D&D 5e System comletely out of the window and created something that I can enjoy.
But currently the bare bones implementation of the 5e combat system in Solasta is about 10 times more engaging, tactical, interesting, challenging and fun for me than the Baldurs' Gate system.
Frankly, I don't understand the complaint of this being some "puzzle solving" game when it comes to combat, cause frankly, almost ANY turn based system is going to basically amount to puzzle/problem solving in some fashion or another, its simply the nature of combat as a whole in almost any genre, especially when faced with an AI opponent. Even Solasta for that matter is HEAVILY reliant at times on you finding what is the best way to take on a fight, or how to best deal with an enemies weakness, the biggest example that comes to mind being the fight against Aksha, as that fight can be damned near hell if you aren't expecting, or aware of some of the mechanics involved, hell even the first real "boss" fight of the game against the first Sorak caster has some elements to it that can be pretty rough if you don't know what to expect, and in a game that requires Iron Man (something which I honestly love to be fair, so no real complain there), it can quickly lead to a game over for your party if you aren't at least aware, or prepared to pay attention to your surroundings, as well as your enemies tendencies. While Solasta definitely does a better job as a whole of being a 5e game in how much it follows the rulebook, and praise be even lets you HEAVILY customize your experience in the settings with various options and sliders, it still just boils down you solving a puzzle as to how best to optimally work your way through a scenario. Same with BG3 ultimately, there is plenty of ways to tackle almost any fight, the problem in both cases becomes just how much people get hung up on the meta gaming/optimal ways of playing, and in this respect, its both the players and the developers faults, players for pretty much optimizing the fun out of the game for themselves, and the developers for allowing a style of meta gaming and min maxing that generally isn't the most fun to do. Albeit, I don't really see the barrel thing being a major issue here, at least not having been a first time player through patch 5, the only instance I actually even ended up using barrels in particular to win a fight was against the Zhentarim which was loaded to all hell with barrels and oil on the ground. As a one off, I don't see it as too much of an issue, but the fact that there are as many barrels around in many, many areas does allow for one to snow ball a fight, or out right cheapen combat as a whole.
Of course, the biggest sin right now is probably just how powerful height advantage is, and I do somewhat wish they'd follow Solastas steps on this one, or at least just retweak the numbers on it, as I do happen to like the idea of having height advantages, just not having it be the end all be all as it currently can be for spellcasters and ranged characters. Maybe have a feat where it adds height advantage as a significant element, and it won't be nearly as much of an issue, similar to speccing heavily into the huntsman stat I believe it is in DoS. No need for it to basically invalidate ranged units on the ground, but also worth giving a bit of a bonus to those who take the time to prepare or set up, if nothing else at least keep the increased range when on higher ground, with an optional feat to increase advantage/damage when higher up. That and I do personally think an action like shove should be kept as an action, rather than a bonus action as it currently is, and that dodge needs to be a feature they eventually implement.
All in all though, there are things I absolutely LOVE about Solasta, and BG3 could absolutely take a few notes from them in some regards when it comes to player freedoms, as well as implementing the 5e rules. For one, I'd love to see a dice rolling system to dictate characters stats, and overall more custom difficulty options, like requiring an action to swap current active weapons/equipment set, as well as having components/a free hand required for spell casting, which I don't think should be a feature forced on all players, but its ones I do particularly happen to enjoy making use of, and can manage to make combat feel an extra bit more strategic, while also restricting the players abilities a bit so they don't wind up being able to do too many actions per turn. All in all, both combat systems do things I really like, and stumble in ways that I think both could learn from each other some, BG3 in general having a far more interesting narrative, world, and ways to interact with its world as a whole, while Solasta generally has the combat feel of DnD down far more, with BG3 somewhere in a cross between 5e and DoS rulesets, which is fine for me as a whole if it were to be tweaked a bit, but its obviously not what many BG fans, or D&D fans really want either, even if I can say that based on the mass majority of players in the CRPG genre, as well as general public reception, it'll perform well critically and commercially regardless of whether they try to keep it more closely to the tabletop rulesets, and likely is just being made to serve as a cross promotion between 5e and Larian as a whole when it really gets boiled down to the basics. Almost would prefer this game was just something entirely of their own making, rather than being tied to the BG universe, especially as how I both don't have much connection to previous BG games, and it would be able to shed a lot of expectations and allow them to more freely create whatever it is they envision without potentially causing some hurt feelings over how people would like a sequel to BG2 to turn out.