Lol well you really do avoid mobile like the plague! The classic pc is trusty. The older the better really because it doesn't come bloated and with tracking.

QubesOS is an operating system (window alternative) which is super secure but a headache to use and maintain.

Librem5 is a phone project launched a few years back as revolutionising mobile phones to make them secure. Or at least be an option but it didn't deliver.