One way is to solve this issue is to use 'gnome-tweaks' instead of the fractional scaling in the settings.
Keep fractional scaling off, then install in the linux system terminal the gnome-tweaks application:
sudo apt install gnome-tweaks
After it is installed, open up the app go to Fonts->Scaling Factor and set the system Fonts to the size you desire.
Matlab will not be affected, and the system fonts will be scalled propperly.
PS: Activating fractional scalling directly on System Setting makes matlab become even smaller, who knows why. And following this https://www.mathworks.com/matlabcentral/answers/406956-does-matlab-support-high-dpi-screens-on-linux#answer_325831 solution does not solve the problem entirely as some checkboxes and serach box will continue very small.
Overall this solution keeps matlab as is, and makes you system have larger fonts! Until matlab scales propperly with the fractional scalling on Linux, this would be a viable solution.
