The Yamaha 125 is a great bike. The KTM has had crank problems and EFI problems since they have come out.
If you get a Yamaha 125, get this kit from Europe. It's a game changer for the bike. Carb parts that ARE NOT AVAILABLE in the US. It is that frekin' good!!!
The GET ignition is also very, very good. I also got a vhm head with a head insert to run on C12. I can win on this bike on a hard pack track against 30 year olds on 450's. And I'm old!
PS I have old bikes and new bikes from a few old 125's to a new 450. My 2024 yz 125 is my favorite bike.