I've had a Nokia N900 and the few Palm/HP Pre models that were released, the former ran Maemo and the latter webOS. Both OSes were based on Linux.

I want a Linux kernel, because even though today I'd list the modern niceties like namespaces, containers, WireGuard, NFS 4.2+, back in the Maemo days, having a Linux kernel still paid dividends. All of the standard networking and WLAN debugging tools you had on desktop Linux were available in your pocket, FUSE meant you could use sshfs, etc. The userland was the same GNU userland you'd find on most Linux distros, you could use X11 forwarding via ssh, GTK apps worked, and you had apt as the system package manager.

I want that again. Android doesn't come close, and neither does iOS.