[bloak]

There are two separate questions here: the one on online identity, and the one on changing a "legal name" (whatever that means). Using a pseudonym online is perfectly normal, in my opinion. I seem to recall that the British police and British school teachers advise people to use a "false" name online, unless there's a good reason not to, as a basic safety tip. So schoolchildren need a good memory to remember all the different names their friends use for different social media accounts. The different names people use could easily be linked by a police investigator, and perhaps by a determined private investigator but it's all rather opaque for the casual googler.

[throwaway250618]

I've started the process and, except for a few places like Twitter, many online services and communities make it pretty hard to use a pseudonym. Especially when it comes to restoring a lost or hacked account, when you have to confirm your identity.

[krageon]

This is true and unfortunately hard to solve. Thankfully, you can prevent losing an account in the first place by replicating your passwords/secrets to more than one place (that you trust not to explode together) and being diligent about fixing failures in that system. For every account where I have done so, I have not lost credentials in over ten years.

As for having your accounts "hacked", the only advice to be given is digital sanitation: Regularly scan your machine, don't give information to places you don't know, don't download shady executables (or if you do, definitely don't execute them outside of a sandbox). These are all good practices regardless, it's just that for you they have become essential practices to keep your accounts.