Hi all you techies.
I have Mac OS Monterey now ten years old and beginning to get 'fussy'
I am very old and really don't want to buy again.
WhenI had windows way back then I installed Ubuntu and while I did not use it for everything I remember liking it and it actually sort of set me up for my Mac which has been trouble free since I bought in 2015.
So been thinking about running with Ubuntu again but see different methods of installation.
I have an 8gb Sandisk USB and wondered if I can download on to that and use Ubuntu as a 'spare' without actually installing on my system.
I use Office Libre for Excel worksheets and that would be one app I would be happy to use as it is now very sophisticated and my Mac cannot seem to handle as it did but this is where I am confused.....
Would I be able to open the sheets with this type of installation.
Am I making any sense ??
I am one of the ancient ones and still got some brainpower but don't get too techie with me.

Opinions and help appreciated.