I honestly think that asking people to PAY for beta/alpha testing access is one of the core things wrong with today's games market. No one should pay to test a game, they should receive something for the effort they are willing to put into it. The more valid information (new bugs found) they submit the more they should get in return imho.
Well, you actually don't pay for beta testing. You pay to be able to play an early version of a game with the promise to get the full version for free upon release. Something like a "serious" Early Access approach (which means that the game is in late development state with an ETA for the final release) is just a preorder with bonus. It's totally up to the customer whether they want to give feedback about their experience. They are not obliged to give any feedback.
In a "regular" free beta people are more or less obliged to deliver feedback. If you want to get paid for betatesting you should join a company which does exactly that. But in that case you have to do it professionally in a controlled environment and not in your spare time for fun.
I think many people miss the point that something like open beta testing isn't valuable other than for testing for example server capacities. It's of much more value to the developer and the game if the people who play a game early are personally and financially invested in the game. That makes the audience both more narrowed and more conscious for serious feedback instead of flamebaiting and internet-bullying (like you can regularly experience during/after short betas for big AAA games). Like I said, Early Access is a way better way to do betatesting for both the customers/fans and the developers. Fans can get the chance to play a game early and influence the direction of a game but only for a game they already like and a game they are ready to invest in early (which is in no way different than just a preorder). Developers can spread the final development stage to polish the game and implement valuable feedback from people who've played the game an people who are invested in making the game as good as possible since they've already paid for it. Without their investment in beta/early access the same game would probably just be released in a much less polished state with way less features. D:OS would probably have been released in February without early access tbh. Larian just couldn't afford to spread development over some additional months without any chance to earn money. With early access (=preorder with beta access) everything is better for everyone. The devs can make the game better and get paid for it. The fans can get an additional bonus for their preorder. The regular customers get a more polished game after release.
Believe me, any argument against a "serious" early access as a part of the development of a regular game are only theoretical and imo invalid. Of course that only applies to games which use early access in a reasonable way which means that it is used - like in the case of D:OS - in the last months and weeks of a game that is already quite finished and a game that a have a narrow ETA. This doesn't apply to these neverending early access games which are published in an incredibly early state (like pre-alpha) which never get any ETA from the devs. That is basically just a cheap way to cash in on a game that you probably don't ever want to "finish". But early access for a traditional game development cycle with the firm goal to deliver a release product at a date is a blessing and not a curse for everyone involved.
So I personally hope and expect that Larian will do early access again for their next game. I'm not so sure about kickstarter since that depends on their financials as well although a kickstarter is a great way to get some public attention and marketing and also a great way to get in contact and strengthen the connection with your fans (and make new ones). The way Larian communicated with us - the fans - so far is imo a clear indication that another kickstarter is highly possible even if they wouldn't really need it from a financial perspective. But only time will tell.