Apologies for the late reply, I agree with achievements being annoying in the newer version and the next major update is supposed to untether characters from specific achievements. I could look to see if I have a version before the achievements update that I could upload for ya sometime soon (~24hr-ish if I have a copy).
From the design perspective, Achievements were added as a way to encourage players to play the different games and try challenges for those games, with character unlocks as an incentive to go for those achievements. But as I'm still learning as a developer and trying out new things, implementation worked okay, but iteration and execution fell flat. I've been meaning to post an update about the game's status, but so far plans are to get the major update to fix this issue out by end of 2023/January 2024.
Have a good day and happy turkey week! :3