I think its intended to line up with the iOS and iPadOS naming scheme. They pooped out an update earlier this year to bring all three OS’s up to the same version number as well.

I’ve had good luck with a couple Latitude 7280 laptops. Replaceable parts, with support for an NVMe drive. There’s only one RAM slot, compared to the 7390 (I think), but a 16gb DDR4 SODIMM stick shouldn’t be hard to find.