^this is the way.

You can buy a domain name for like $10 per year; I recommend getting it from porkbun.com.

Cloudflare.com is good too, EXCEPT if you buy your domain from them, you'll be required to use their nameservers until and unless you transfer your domain elsewhere (which you won't be able to do for a while). Though to be fair, their free DNS is good and lots of people use it anyway. It makes email setup slightly more complicated, but it's still doable.

Spaceship.com also has a pretty good reputation, but I think their customer service isn't as good, they're quite new, and they're owned by Namecheap (a bigger domain registrar with a much worse reputation).

Whatever you do, DO NOT buy from GoDaddy. Do not even search for the domain you're considering on GoDaddy. Literally any option is better than GoDaddy.

By far the most reliable TLD options are .com, .net, and .org. These will look relatively trustworthy for email, and the price stays very very stable from year to year. If you don't want to think about it, just get one of these. You can even still find single dictionary word domains for .org or .net relatively easily.

Do not buy any domain marked "premium". This means the owner of the TLD can change the price at renewal as dramatically as they want, for any reason (e.g. if you have a website hosted at that domain that becomes popular). Your $20 per year domain might suddenly become a $300 or $3000 per year domain for no reason but greed, and you wouldn't be able to do anything about it.

Non-premium nTLD's (.club, .horse, .rocks, .theater, etc) can increase quite dramatically in price, BUT the price is required to be set the same for all domains using that nTLD, so they can't target any individual person for having a successful website or whatever. Also, you can pre-buy up to 10 years, which locks in your price for those 10 years. I'd still not recommend them for a primary email, but it's better than buying a "premium" domain. Just be aware that the yearly price might unexpectedly increase in the future.

Some country code TLD's are also good, but for email, probably stay away from the ones that spammers like to use.

___

Anyway, what I actually originally meant to comment about is: if you set up forwarding from gmail and don't check that account regularly anymore, I recommend setting up a gmail filter rule that forwards all your gmail spam to you (their regular forwarding setting leaves it out and just sends it to the gmail spam folder). It's a little annoying to have to re-flag some of the spam as spam in your new email, but gmail has a habit of marking non-spam as spam for me, and if you're not regularly checking that spam folder you can easily miss important email.