Help with insights on changing a repo on existing site

I’ve made a new version of my client’s site (using a new git repo) and just as I was going to link the site to a new repo I stopped when asked about adding env variables. I have several already but they are not shown in the link-a-new-repo dialogue. Are all my current variables get deleted in the git-swapping procedure?

That creates another worry in my head - what about build hooks, deploy keys, and notification settings, will they be erased as well?

I would very much appreciate it if anyone with git-swapping experience share a few words.

Everything is preserved when swapping a repo as far as I know.

Thank you @hrishikesh for your time and effort.