Here’s how to disable PPA: https://support.mozilla.org/en-US/kb/privacy-preserving-attr...
Though even without disabling it, PPA is currently in limited rollout and only visible to Mozilla websites in the first place, so it would hardly cause any harm for now.
[1] https://blog.mozilla.org/netpolicy/2024/08/22/ppa-update/
When I was using FF, i noticed that updates often revert settings to default. What pissed me even more was that there is no clear "Disable auto updates" checkbox, I had to create policies.json file in Contents/Resources/distribution folder for that. This was hostile, I'd never win the battle with developers.