I'm running the pre-release version of RA and I'd like to hide these error popups, is it possible?
That's not possible no, though all of those requests failing looks rather suspicious.
already filed a bug report ^^
You could try turning off semantic highlighting in the VSCode settings to at least prevent the pop up from appearing as you type. Not 100% sure if VSCode will stop requesting them then though.
now the crashes are reduced to "only on hover". It's an improvement