Sadly, the options are rather limited.
Palemoon (https://palemoon.org)
is what I use as my primary browser. I they are better off as far as the privacy/security is concerned, but certain features, like webRTC are intentionally disabled. DRM video sites won't work either.
For unsupported features, I use Firefox. Privacy is slightly better than chrome/chromeium I think, if you disable google safe browsing.
The rest of the modern browsers out there are based on chromium, so it probably won't be much of an improvement.
I would highly suggest using ublock though, Ads now use up a lot of CPU and memory, some even trying to mine crypto currency with your computer.
Because I'm not happy with the current browser landscape, I've been working on my own browser, including rendering engine, from scratch, but is isn't ready for use yet.