Atkins from 2020-23 was a better GM than 2010-15 AA, but current AA is better than Atkins. If AA stayed in Toronto and didn't have that time in LA, then it's hard to say what type of GM he would have been from 2016 onwards as the Jays transitioned out of the small window that he created and into the next one. Atkins from 2017-19 was kinda ass as a GM if you look at the totality of his moves during that span, but something clicked in 2020 and he became a lot better. It's an interesting "what if" though.
As far as what the Jays do over the next few years, it really depends on what type of internal development they get over the next two seasons (2024-25). Davis Schneider practically fell into their laps and they aren't playing him as much as they should so not sure what to think about how (or if) they'll be open to giving prominent roles to young players during a competitive window. If Barger is suddenly the 3B/RF, Orelvis at 2B, DS in LF/2B, Roden in LF/RF, and so on, then you could picture a scenario where the team can still be competitive if they use the saved money on expensive FAs again. That's what made them successful during the 2021-23 window. They'll have to recreate that but maybe with quantity over quality (meaning a bunch of 2-3 WAR young players rather than hoping for 5+ WAR performance out of Bo/Vlad and never getting it, at least from Vlad).