First thing I would recommend you switch is your email, if you use gmail. Buy a domain for yourself - they can be as cheap as $5/year. Most email providers (at least any good ones) will let you use your own domain. Now you own your email address(es), at least to the extent that you can own a domain name. Whatever provider you use, you can switch without changing your email address. Personally I use Fastmail and I love it but there are plenty of others.

It's a long process to switch over, because you have to notify contacts of your new address, change your address everywhere, etc. You can keep your gmail address forwarding to your new address or pull it in via POP/IMAP to the new account and continue getting emails that go there. Every time you do, if its anything other than spam, update your contact info with the sender. It took me about a year before I stopped getting any relevant email at my old gmail address.

For Google Drive... I've never used it so I'm not sure what all it does but MEGA is decent for sharing large files and cloud file sync - I use that on my work laptop. At home I have a NAS server.

For search I use DuckDuckGo for anonymous searches and Google for localized ones. You don't have to be signed in to use Google search and nothing beats the results it gives for certain types of searches, though it's been getting worse and worse.

YouTube, again the same content isn't going to be available anywhere else except the few channels that publish on other platforms, I use invidious on desktop, YouTube links are all redirected there except when coming from invidious "Watch on YouTube" link, or directly entered into the URL bar. On mobile I am using Newpipe, you can also check out YouTube Vanced if you still have a lot of subscriptions you don't want to transfer over yet or want to use something more like the official app... Vanced is the official app just with no ads and some extra features added on.