Ask HN: Google Account Recovery

I know this gets brought up occasionally; but I've been locked out of a google account that belongs to me for about half a decade.

It is linked to another google account that I actively use, I'm not sure if I remember the password to the lost account(since google won't let me into the account). But I routinely use the linked account.

I'm denied access to my account on the grounds that I'm logging in from an unfamiliar IP/device, however my parents moved to a new home when I'd gone to college, and since I was at college I no longer had access to the main IP address that I was logging into it from.

My browser settings have been set to auto clear cookies on close for as long as I can remember. So it didn't recognize any of the devices I routinely use to access it.

I'm trying to get access to that account so that I can deal with what I have to, and then delete the account.

What recourse do I actually have for the same? I've recently switched to Posteo since I never want to be held hostage like this by Google ever again, but it doesn't resolve my original issue where I'm being unfairly locked out of my account because google doesn't trust me...

Literally any help would be a godsend.