Tutanota have been around for a bit over a decade. They close unused free accounts after six months inactivity.

Their main focus is end-to-end encrypted email. When sending encrypted emails outside of their ecosystem, they used to send a link to a temporary account, so as to reduce the chance of a leak.

They've never been hugely popular, but their name pops up a fair bit in circles where legality of things might be a bit gray. Like countries where certain human rights are suppressed, or where Tor is needed to workaround only getting government approved sites, etc.

> ProtonMail is known for completely arbitrarily closing user accounts with 0 recourse

Never had an issue with them personally.