I tried that after already having about 2 years experience with Ubuntu desktop and an Ubuntu server (but still mostly a Windows user). I’m also a software developer.
And I failed to install Arch on a laptop the last time I tried it out. Ubuntu ran flawlessly, trying to go step by step through the Arch installation I hit a random error (at a step that was very straight forward and easy in the documentation) and got stuck. Messed around with it and at some point gave up.
I mean that’s years ago, it probably works a lot better nowadays and especially on more modern hardware, but even so for someone new to Linux I’d never tell them to go with a do-it-yourself install. Slap Ubuntu on that bad boy, let them install a few packages, do a handful of terminal commands and they’ll get much farther. Instead of giving up three hours in because a random command (that they still don’t understand) is broken.
But as OP said, they already failed several times. That’s like telling someone who nearly drowned in the shallow end of a pool to go jump into the ocean.
See here:
For me it feels like they do want to learn, but aren’t comfortable yet as a day to day user. They want to use Linux, but struggle with commands and how to use it. Having a stable and easy to use system you can use each day without trouble would probably be a better start than telling them to fiddle with Arch. Give them an easy distro and when they want to learn more they can use the crappy old laptop and try to install Arch on there (while leaving their daily driver alone).
I think I learned the most when using Ubuntu for school, 90% of it was easy and straight forward. 10% of it was hell, like back in the day getting HDMI or audio to work. But because the 90% were there I just dug in and spent a dozen hours to troubleshoot the rest.