Good work, thanks, it will improve the developer experience a lot! I would be really happy if you could make everything work without any @ts-expect-error though 😇 (but it's ok if you're not motivated for that 😁)

I've fixed a few other TS errors but I feel that the most important is to add Typescript as to not make any further type error: we can fix the remaining errors when we change the related code
Moreover, I believe that most of the remaining errors come from the fact that the data from the backend API is untyped, which we will be able to fix later!