As I understand, you CAN
Here is two tools for that:
Prevents even from JS detection, you can use it for spoofing only one user agent if you don’t need random features.
Personally I use it on tablets and phones in Firefox to fool crappy websites like Pinterest or TikTok that I am visiting from PC and not to annoy me with mobile apps.
randomizing your user agent is not going to prevent fingerprinting completely, camoufox may be valid but I will not comment for sure without knowing and arkenfox exists.
Just use Mullvad browser and blend in
It is more to hide OS. It will slightly reduce fingerprinting as you will look like windows user.
But note NEVER set chrome user agent when you are on Firefox (some fingerprinting scripts check spidermonkey behavior).
Just set something really popular. Like:
Firefox on Windows (valid user agents can be found on useragents.me). Set CUSTOM user agents in main settings of extension