Sorry, I won’t request changes to third party plugins.
Third party plugins should work like in “WordPress without the block editor” as ClassicPress is described.
If ClassicPress changes more than that, it’s a ClassicPress problem.
Gave the ClassicPress project a try today to get an older WordPress 4.9.22 site to be PHP8 compatible but as it seems it’s actually too much of a hassle and actually causes legal risks for client because of mentioned prefetch and maybe similar other yet unknown effects. Also ran immediately in another problem described here which was almost an immediate showstopper already. So I guess, we will not dig into this any further.
Thanks for your quick support though.