I use both, but sometimes it's a bit a pain in the ass with capchas and and embedded iframes etc. A lot of trial and error which scripts are needed. But it's great to know most of the crap, including cookie/consent banners are blocked.
The first time I log into a website I often need to do a few rounds of "allow this script; refresh; allow this script; refresh" to get captcha/cdns working. But then I save for that site and don't think about it again. It can be a bit of a pain sometimes, but I find it interesting having to acknowledge where different sites pull resources from.
The Stylus extension is great for that. Firefox's style editor lets you test CSS edits in real time. Then copy those CSS rules into Stylus and the browser will remember them. I use it to turn off all CSS animation too.
If you block all JS and CSS with umatrix, you can still read articles by pressing the "reader view" button in Firefox.
If you want something a little simpler try scriptsafe[0]. Still lets you whitelist JS you want to trust, enable temporarily or for a set time. I find it rather clearer than uMatrix.
In fairness to gorhill it's a couple of years since I last looked at uMatrix so it may be much improved.