I do a bunch of CSS work, and I've found more bugs in Chrome's rendering than in Firefox's, Lots of half-pixel errors. What kind of rendering issues are you seeing in Firefox?
If you do a lot of web development, I strongly recommend getting familiar with Firefox's containers. You can set up SOCKS proxies for each individual container so you can easily pretend your dev server is running on the production server's domain without disabling your own access to the production servers. It's so much nicer than working with multiple proxies in Chrome.
That said, you might enjoy ungoogled-chromium if you're annoyed by google-integration. I use it for testing (because cross-browser testing is still a must). Brave also exists and is open-source, to break up market share.
I'm sure that Chrome's rendering is buggy as hell, but people design websites to work with the bugs; so they design them to work with Chrome, and in Firefox they look wrong unless they make the effort to work with both browsers.
I'm not a web developer; when I have to do web development I use Chrome because that's what we target and anything else is an afterthought (or is work taken on by more specialized frontend developers).
I tried ungoogled-chromium, but on upgrades it would frequently crash or fail to start so I gave up.
Brave maybe is worth a try; the cryptocurrency tie-in was enough to make me reluctant even to give it a try. I want my user agent to be as agnostic as humanly possible with regards to presenting data from web pages -- that's why I hate the auto-login feature and the "view search results" feature; I want my browser to render content and do only the minimum possible work in reacting to that content.
If you do a lot of web development, I strongly recommend getting familiar with Firefox's containers. You can set up SOCKS proxies for each individual container so you can easily pretend your dev server is running on the production server's domain without disabling your own access to the production servers. It's so much nicer than working with multiple proxies in Chrome.
That said, you might enjoy ungoogled-chromium if you're annoyed by google-integration. I use it for testing (because cross-browser testing is still a must). Brave also exists and is open-source, to break up market share.