Yes, I style my LibreWolf/Floorp desktop applications to suit my preferences/workflow and I spend 8+ hours a day using them. I hide elements I don't need, make my sidebar tabs auto collapse/expand when I hover over them, change the scaling factor. While yes, the basic design is good and works for 90% of people that use Firefox, I have over the last decade developed a personal a workflow that works very well for me, and i would argue is much more efficient than the average users. The advantage of open source software is that you can mold them into the shape that suits your preferences.