So it looks you are only looking for someone to say what you wan to listen
Ubuntu breaking X11 its really from the past, like 2012, last time I remmeber to have the issue, that was also when I started to use Ubuntu, thus maybe was a rookie mistke, spcially when I was comming from Windows.
I don’t know Manjaro, but what kept me on Ubuntu is really the out-of-the-box just works.
Ubuntu 18.04 here, and a picture is worth 1000 words, thus here it is one after a restart:
I think that this is more a concern about if the graphics in the motherboard of your new Laptop support it.
You can always use the selinux or apparmor to tight things up.
Also you can use LXC containers to run another Linux distro inside your current Linux distro. So like one for work and another one for personal use.
My approach is to use heavily docker for my developer flow, everything runs inside a docker container, even my code editor.
For personal use in sensitive stuff I always use Firefox from inside a docker container, like when banking.