I have a gmail account that is connected to my Android phone. I don't use it for anything else, so it's unlikely that I would run afoul of Google for anything I do with it.
Any hosted email, paid or free, is going to have terms and conditions and you will be able to find anecdotes from people whose service was suspended "for no reason" but it's that or buy your own domain and host your own email.
> it's that or buy your own domain and host your own email.
Those aren't the only two options, there are two in the middle ground (and perhaps more that I'm failing to think of) that are well worth considering.
Option 1:
The best option IMO (what I chose, anyway) is to buy your own domain, and point its DNS MX records to a reliable email provider, which can even be gmail (though they're not who I chose).
That way you get almost none of the hassle of hosting your own email - it's very quick to set up the DNS records when you first get the domain, easy enough that even non-tech people can follow a simple tutorial, and after that you don't have anything to manage - and you don't need to worry about whether your emails will look trustworthy enough to avoid going straight into most people's spam folders (so long as you pick a provider that most of the world's email servers do tend to trust, such as gmail).
But if you do get locked out by the email provider you choose, you can point the DNS records at a different provider and not have lost your address. Obviously it's slightly more expensive than using gmail for free, but it's fairly cheap, affordable for many people (though not everyone).
Option 2:
Alternatively, if you need to stick to a free solution, you could create a free account at two different providers (let's say Protonmail and Gmail, or Hotmail and Yahoo, or...); have one of them as your primary email account, that you use like normal, but use the other one for signing up to accounts that would be a problem to lose ability to receive emails from.
Have the second account set up to automatically forward everything to your primary account. That way, when you need to click an email verification link, or open a password reset email, or whatever, it will have been forwarded to the inbox you use normally, so there's no extra hassle. But if you do lose access to your main account, you can still login to the account that receives the important emails to access them directly and to change it to forward to a new primary account elsewhere.
Of course there's still technically a risk that your important emails account could also be shut, but if you are only using it to receive emails from companies that you create accounts with, and you're never sending anything from it nor using it for any other services (ie not also using it for YouTube or similar) then the chances of losing access are almost as low as the chances of that business completely disappearing without warning.
Note that you need to be on a paid Google Workspace plan before pointing your DNS MX records at Gmail as provider, or else your emails will either be rejected at best or simply vanish into thin air in the worst case.
Oops yeah I forgot to state that, thanks for pointing it out.
There are cheaper options than Google Workspace (which is £11.80/month) for quality email hosts for your custom domain though - like FastMail (£4.50/month), ProtonMail (£8.19/month), or Microsoft 365 Business Basic (£5.52/month).
Personally I think it's a price well worth paying for knowing you genuinely own your own email address (while not having to manage both the software and the reputation of your own email server) - even more so if you either have friends/family to share the cost with (one domain cost between you, and potentially discounted per-account cost for multiple users depending on the plans available from the various email host options, such as Fastmail family going as low as $2.33/user/month), or if you also want other services bundled with email (such as Google Workspace's other tools, or Office 365 software, etc)
But for anyone who can't afford it, the free alternative of Option 2 from my comment above is still a big upgrade on just relying on a single account for everything.
Any hosted email, paid or free, is going to have terms and conditions and you will be able to find anecdotes from people whose service was suspended "for no reason" but it's that or buy your own domain and host your own email.