I switched from Gmail to Proton, but now with everything coming out about Proton I'm switching from them too. I started using Posteo which I like but a lot of my accounts having to do with money and finance (including my bank) aren't accepting the Posteo email. They have rejected it over and over and even locked me out stating that I was hacked.

Do you guys have any recommendations for email providers to use that also won't send red flags to my more official accounts?

If it helps, I'm US-based.