Just replying to my own comment to say that folks should think very carefully about switching to a personal domain name for email, for the very reason mentioned by the OP.
What if your domain registration lapses and someone else grabs it? What if you can’t afford the cost five years from now? What if you just don’t like the domain name someday? All of these reasons will be problematic and some can result in identity theft and significant fraud. It’s definitely not a decision to be taken lightly, particularly if you have a lot of online accounts.
No, once you delete a Google account it can never be used again, by anyone (link).
I use a password manager (KeePass XC/DX) to track all of my accounts.
In your situation, I would update whatever accounts you do know about to the new email address you intend to use. Set Gmail to forward emails to this account too, and then stop using Gmail for everyday mail. Leave your Google account active for a year and see if any issues crop up.
I can’t say that I’m surprised when a privacy-focused company has a dose of unfounded or biased paranoia. For me, this is not reason enough to distrust them.
I also don’t fault them for doing away with SMS when most of the populated world had already moved away from SMS by then too. As a North American relying on SMS for about half of my messaging needs at the time, I wasn’t happy about it either. But I don’t fault them for making that decision, and ultimately it did push me to rely on more secure options, which I see as a good thing.