This was in case OP didn't want to give up Gmail straight away. Of course you can just migrate to another provider, or, as in my case, spin up your own mailinabox[1] instance. That way the only provider you have to deal with is the cloud provider for your VPS, and in the remote case my account was terminated, it would be very easy to switch to a different provider (because Mailinabox includes functionality to do automated backups to an external location).
I've thought about doing this myself, but apparently it's a lot of work to get right. I read from others who tried it that a lot of their mail would be caught by spam filters and they didn't necessarily know why.
I've been using mailinabox for almost a year, I had an email caught in spam once, I contacted the spam filter and said my IP was probably being used by someone else before I took it, and they whitelisted me.
So you can have an occasional annoyance but it's not that common.
When I get a new IP (e.g. because I'm upgrading to a newer machine) first I check my IP against a list of antispam filters (I don't want to advertise any of those services, but a quick internet search will show you where you can check, most services have a free tier), if it turns out that the IP has got a bad reputation, I just get a new one instead of trying to whitelist it.
The only time that my email got bounced, that IP was not "clean", it had been blocked by one of the filters but I thought "oh I will just whitelist it on that one filter". I should have generated a new one instead.
One more thing that some people might not know: with all spam filters, if your email is caught by the filter, you will get a message, it's not like you don't know if the email has been delivered or not.
You will see something like "Your message could not be delivered - The mail system [host, ip] refused to talk to me: [reason, e.g. spam]"
[1] https://mailinabox.email/