You won't keep the same address unless already use a custom domain. Most email providers will let you import emails from your old account, then you just change your email address in any accounts to your new one. You could also set up email forwarding from your old address while you sort it out.

Check out the r/degoogle subreddit. Plenty of great resources in the sidebar. I've switched to Fastmail, Filen (cloud storage), Librewolf (Firefox fork) with DuckDuckGo search, installed GrapheneOS on my pixel. Youtube is harder. I use Newpipe and Freetube where I can, but it's a process.