How to manage all your emails and store them online?

Hello,
I have multiple domains, maybe 30, and in all of 30, I have a custom email. Is there any way to check and store all emails online so that even if I change the device, I still can see them all?

I manage them with Thunderbird but I should install it on all devices, and I was looking for an alternative and better solution.

Please advise; thanks

Maybe you could use something like gmail, where you can connect external accounts allowing you to receive everything to the inbox but also to send as those accounts?

I sued to use Thunderbird but found it a bit buggy.

It is hard to beat Gmail or Outlook on a desktop and sync either of them with a desktop