My experience of Starship on Windows has been great. I'm using the Windows native builds of both Starship and git (both installed/updated via winget these days) in PowerShell.
I try to avoid emulation layers like MSYS2, as much as I'm able.
Also, yes, if git hangs on git show/git diff that sounds like an antivirus problem or a dying hard drive or the first one causing the other one.
Or just a really big git repo. Starship includes a timings command, on linux (with an annoying antivirus meddling) this is what I see against one directory:
If I go in to my checked out version of the linux kernel, probably the biggest git project I've got kicking around: That's typically the worst I see it.