I'm running through my head thinking of all the things in my domain account. Email archive/filters/rules, contacts, calendar, docs (mine and things shared with me), Drive, photos, Play purchases, Google One subscription for extra space, Android, Google Cloud.

Then I have stuff on a plain @gmail account that didn't work with my domain account - family library, links. That was already annoying. Don't want to mess that up either.

Should I merge the accounts or create a new @gmail account to hold everything?

My estimate is that it will take days of migration/backup/testing to move over, then extra time to ironing out issues that crop up. Hopefully I don't lose any content or purchases...

Even with email forwarding I believe I'll lose cosmetic things like using your domain as the owner of calendar invites, photo sharing, etc.

This is for 1 email account/domain only. I think I'll probably pay up.