Probably worth mentioning that another alternative called TopAnswers.xyz exists as well—both Codidact and TopAnswers mention each other in their homepages, which I find pretty neat.
Definitely interested to see how both of these sites pan out. StackExchange has been a powerful force for good over the years, and it's been sad to hear it starting to slide down recently, not that I should be too surprised since they got bought four years back. I'm eager to see what a properly open-source and nonprofit community can do on the good template that SE once set.
I do wish either of these sites could host in a different country than the UK though; I've heard more than enough by now to feel that hosting a tech project in the UK is scarcely any better than doing so in the US, privacy-wise. (Though for that matter, TA uses Amazon for hosting, which is probably the worst of both worlds.)