What other free options are out there? Proton Mail’s free plan restricts to only 3 folders.
EDIT: After careful discussion with others, I’ve reluctantly decided to stick to Gmail, because we don’t know if these other providers will still be around 50 years from now.
I just pay £5 a month for server hosting, which includes unlimited mailboxes I can connect to with Geary and K-9 via SMTP.
Did you set everything up yourself? If so how is it going, what mail stack are you using?