Yes...
Final Cut does a fairly remarkable job of upscaling SD footage to HD. Unfortunately, adding Effects to the footage (not just Color Board) will actually turn off that upscaling.
There is a "built in" Sharpen effect in FCP, but it sucks.
Try this one instead:
https://fcpxtemplates.com/sdm_downloads/sc-ez-sharpen/
Install as an Effect (if you need help: https://fcpxtemplates.com/installing-plugins-for-fcpx/).
This is a barebones effect for sharpening, extremely lightweight. You can add it first or after other effects.
I recommend trying to NOT go over 50 unless absolutely necessary. Grab hold of the slider and watch the screen very carefully — you want to "just reach clarity" and don't go beyond it (it will start looking a bit harsh and although it might look clearer, it's not generally what you'll want.)
Hope it helps!