BXT Bestseller MTB Carbonrahmen 24 Zoll Scheibenbremse Kinder-MTB-Rahmen Geeignet für 135cm-150cm Kinderfahrräder

Frame and fork are perfect for a top kids 26er build.
Front internal routing and rear + brake external routing is a good compromise between look and maintainability. Front derailleur inner routing can even be used for dropper post internal routing, the frame is compliant at bottom bracket level.
The use of old standards (QR135, non-boost) allows to reuse dad's high end 26 components (wheels and fork), for a 8.5kg full bike with rigid fork.
Why not 5 stars? Included seat collar was the wrong size, and lack of communication with the seller on shipping delay (but packaging was perfect)

Great looking frame. The design they came up with for the rear dropout to run either QR or Thru axle is actually really cool. Paint was don well. No issues with threading in the BB. The only issue I had was there was a small buildup of carbon/resin where the lower headset bearing needs to be seated. I had to do a very small amount of touchup grinding to get the bearing to seat properly. If it wasnt for that, this would be a 5 star review.