DSi introduced region locking to Nintendo handhelds. I stopped buying them at that point. The next Nintendo system I bought was the switch, which was no longer region locked. The DSi kicked that off, so it might be my least favorite.
Favorite hardware is a much tougher nut to crack. Could be my first console, n64, or my first gaming apparatus, the Gameboy Pocket. But the PSVR1 blew me away and made me a little less into flat games. The PS5 has everything I love from PS4 onward (and does VR), and the Steam deck streams my PS5 from bed while also playing pc, retro, and Xbox games and being a full on Linux machine.
Home consoles were region locked based on physical barriers in the slots that would block a cartridge from a different region. You could just extract those barriers and the console could play any cartridge from any region, though. Handhelds had been different, though. Up to the DSi, you could buy a handheld cartridge from any country and it would plug in and play no problem.