Depending on the model you have, it might be possible to move some stuff to a microSD card. Ultimately if you're that close on storage you'll benefit from freeing up space because it has to constantly search for scraps of space to store stuff even temporarily which is a major performance drag.
also if you have a newer model it might be possible to replace the SSD with a larger one.
My Surface Go 3 is low on hard disk space, but that's because I have two operating systems (Windows and Android) installed onto it. I keep the Documents folder and the like on my SD card, along with some apps. Symbolic links is a godsend for moving files from the hard disk to the SD card. Fair warning, there's a learning curve!