If I switch from VS Code to VSCodium, will I notice anything different - assuming the telemetry is not really visible to me and I ignore the branding?

Will the plugins - some provided by MS - still work as expected or will those be blocked or hobbled?

Thanks!

Pylance won't. There's the EEE you're looking for.

IIRC there was a ticket somewhere in the issue tracker where someone explained in the comments how to get Pylance to work. Wasn't particularly difficult.

https://github.com/python-lsp/python-lsp-server

Someone might come along and tell you that you are missing out on some pylance features, but fuck closed source dev tooling it ain't worth it.