Right, supported version is only 2.x, further down running 5.x via wine it says “more broken than version 2.5”.
Maybe you can give a console based workflow another shot? I ended up using only git + tig + whatever webui is provided (github, gitlab, forgejo, etc). lazygit is also nice, but I use it rarely.
2-3 days seems very optimistic, but it depends how much you enjoy tinkering with your setup.
Maybe consider dual-booting so you can go back to windows if something urgent comes up while you migrate.