My issue with fast mail et all is storage is so unnecessarily expensive. I have many gigs of email that I don’t want to lose, but I also don’t want to pay many tens of dollars/month to host it.
How many gigs? It appears that the 100GB plan is only $9/mo.
In addition to the iCloud, I have a free ProtonMail account, which I use sparingly, and anything large or important that comes in there I move to local backup and delete. 99% of the messages I get can just be deleted. If you set up pop3 you can auto delete from the server. That’s the old school solution, but it depends on your use case. The pop3 option doesn’t work well with multiple devices.