Receiving email is no issue on residential ISP.only issue is sending, And to get around that you simply use an external SMTP server and your problem is mostly solved.
Yeah, that is one workaround that is reasonable to use. I'm just a bit weird and want to do delivery to other servers without an intermediary :P
It's just something you have to do anyway since more ISP prevent sending directly from home connections. That means it will cost some money, but there are also SMTP services with free tiers for several thousands of emails per month.
ISP mail relays generally work, not sure why you'd pay to add another MiTM besides the one that already exists (your ISP).