I haven't had many problems with the Guest Additions lately as most mainstream distros are baking the utils into the kernel now. I haven't tried MX Linux in VBox though since I have it on the rails on an old laptop and desktop.
I decided to archive my VBox installs of Sparky and Ubuntu to save some disk space, and I am just running Mageia on Windows as my Linux go-to distro.
You're doing it backwards Ray. You don't run a solid & stable guest on top of a quirky & buggy host. You run the quirky & buggy OS as a guest on your reliably solid & stable host!