What don't you like about the linux cli? is it a UNIX thing or a GNU thing that you don't like? What makes CP/M like systems (CP/M, DOS, OS/2) better in that regard?. Personally I strongly recommend the Pi 400 for a first computer. Of course, that all depends on the child of course but the Pi 400 and 500 desktop kits are really great and the Pi 400 is cheap enough to not care that much about it breaking while still feeling more accessible than just a Pi in a case (or any desktop computer really, I feel like AIOs and Keyboard computers are the most accessible)
Now that I think about it, actually I don’t have anything against Linux cli. After all it is my daily driver. I just want to jump into QBASIC and show him how I program simple stuffs. In fact, DOSbian is from Ubuntu AFAIK.
I know raspbian comes with scratch which is how I first got into programming (and still mess with from time to time, made a bf interpreter once). For the basic concepts i feel its easier for a little kid to grasp since the sytax is graphical