We have a fedora repository available with which you can install LibreWolf. You can add it to your system and install LibreWolf by running the following commands one by one:
If it doesn’t rely on dependencies provided in the normal Fedora repositories, then theoretically it shouldn’t be a problem. If it does, then said dependencies could be newer versions than the ones provided in Rocky, and then you wouldn’t be able to install the packages.
Normally it’s not recommended to use repositories for other distributions purely for the reason it could get your system into an unstable state, or overwriting OS packages with newer ones and then causing a dependency nightmare when you then try to update your system.
Without actually adding the repository and attempting to use it, difficult to say. Perhaps build a VM with Rocky, and then add the repo and see what happens.