

I will with you halfway through with this, here is how I view it.
If you have little experience with telling between safe sources and sketchy, then yes, stick with the defualt.
If ypuu know about some safe appstores or repositories then that’s when you could say you are qualified to make thes decisions. Like I know Fdroid is safer and better than the defialt on everyway for the users best interest, but if you dont know your sources then you should not sidelode untill you do know how to make good decisions.
I don’t think it would be illegal unless it’s a Chromebook they lended to you directly to work at the company. If you went to a store and bought it your self it’s perfectly legal to throw ubuntu on that Chromebook.
Here’s where things start to get harder though…
Whether they will fire you… eh idk if I would take that risk. But if anything just ask the people working there for their opinion on it.