Ubuntu GNU/Linux is not entirely FOSS, as it ships with non-free software by default. If you're committed to FOSS principles, I would recommend Debian GNU/Linux instead.
However, it's important to note that Debian GNU/Linux is not recognized by the Free Software Foundation (FSF) as a completely FOSS distribution. This is because Debian includes non-free firmware packages for those who need them.
From a security perspective, this is acceptable, as the Linux kernel won't load these packages unless the corresponding hardware is available. Debian ships with Free Software by default, and I would suggest giving it a try if possible!
It's essentially the same as Ubuntu, but more freedom-respecting.
Even when they get a new user on Linux, they still then scrutinise their choice of distribution, if not that then their IDE. There's no winning and it's off-putting for people considering the jump.
I was simply offering a suggestion. The original poster used the term 'FOSS' to describe Ubuntu GNU/Linux, which isn't entirely accurate, as Ubuntu includes non-free software by default.
My intention was to ensure they were informed about it. The whole point of GNU/Linux is to make sure that every computer user has freedom. If you think sharing information and teaching people is bad, maybe you're using the wrong operating system.
Completely FOSS isn't completely self-sustainable either in the real world - you'd need to be using something like RISC-V with coreboot and a completely open hardware stack with zero proprietary firmware blobs in the mix + not to mention running a fully self-hosted email/cloud stack. And if you're using a mobile phone - even a dumb one or a pinephone - then you're not fully FOSS. I'm not aware of anyone who's fully FOSS out there, except maybe RMS?
TBH, once stop running Windows, everything gets easier. And if your running Ubuntu or Mint, it's not even that painful to start and hardware more or less just works.
Debian is nice for servers, but it's a little out of date for desktop. YMMV, welcome to the club and ignore the snobs ❤️