That happened to me, lost 16 years old gmail account, which is my main account for my digital life. It happened after I disabled some tracking, and Google was no longer able to recognize me, even though I had my phone number registered, it was not enough.
I suspect this will happen to me soon, though all I do with it is occasionally sign in just to keep it registered. It now refuses to log me in unless I am on a specific IP address, no matter how many MFA steps it requests and I pass.