Just updated to Sonoma (14.1.2 (23B92)), and I'm also experiencing problems with Firefox (120.0.1) on an Intel-based MBP (2.3 GHz Quad-Core Intel Core i7, 2020). Firefox does work, but tabs regularly get stuck on opening. If I wait long enough I get an NS_ERROR_FAILURE error when I look into the network debug console. Strangely, this is intermittent (the same site will work once, and then hangs the next), and loading the site in Safari (sic) usually gets Firefox unstuck when I reload the hung tab. I suspect some name space resolution issue, possibly with some caching involved within MacOS. I've tried to activate http logging inside Firefox while the problem was occurring, but I cannot make sense of the trace I got (NS_ERROR_FAILURE does not even appear in the log file).
