Yes, decent Con + proficiency in Con saves means that with some levels in you, you won't fail any concentration checks unless things are hitting you for big damage (like 30+ damage hits). Throw in warcaster feat for added goodness.
I get that you are just sharing insight to those unfamiliar with 5e, so don't take this as a slight against you, but this is a topic that's pretty frustrating to me so I need to speak my piece.
Being forced to take an early feat for Resilient(CON) or Warcaster at level 4, just to be able to maintain concentration for a decent amount of time in BG3, is bad design in my opinion. This prevents you from increasing your spellcasting modifier, so you will be less likely to land your spells. Spell casters that want to use their spells to hinder their enemies are going to be nerfed either way. Either they take the feat, and they will be less likely to be able to land their spells and make use of their concentration in the first place, or they boost their spell modifier so they can land spells, but lose concentration every other turn because they won't be able to pass the wave of concentration saves they are subjected to.
Not only that, but these feats still won't change the fact that you are making more DC 10 saves. Let's say you have a decent +2 CON with proficiency in CON saves. That's a +5 to conc. saves for most of the game, which means that you still need to roll higher than 4 to pass a minimum conc. save. 20% of your conc. saves still fail, so if you have to make 3x as many conc. saves than you should, the usually infallible Resilient(CON) or Warcaster still won't guarantee your ability to maintain concentration.
Feats are supposed be a way to add flavor or achieve a superior ability to solidify your role. You shouldn't be forced to take a feat just to be somewhat decent at what you were meant to do in the first place.
