im useing edgeI personally wouldn't recommend using an extension for that. There are still websites with about:config tweaks for Firefox that are updated regularly.
Here are some of them mentioned by @oldschool in another thread:
These are the tweaks you should make, settings to you should set, and extensions you should download to make Firefox more privacy friendly.avoidthehack.com
Firefox is popular in online privacy communities because it is a high quality, open source web browser that is extensively configurable. Unfortunately, those...www.quippd.com
You might want to check out my config. I have a list of some useful Firefox privacy tweaks. Only enable them, if you actually know what you are doing.
For enhanced privacy and security I recommend those basic ones. They are effective but usually don't have a huge (negative) impact on browsing:
1. privacy.resistFingerprinting = true (Probably the only one that might conflict on some pages. As the name indicates, it protects you from browser fingerprinting. Read more here: Firefox's protection against fingerprinting | Firefox Help)
2. fission.autostart = true (Enables site isolation for enhanced security)
4. webgl.disabled = true (Prevents sites from seeing your graphics card model)
5. geo.enabled = false (Prevents sites from seeing your location. It can still be tracked by using your IP)
6. media.peerconnection.enabled = false (Disables WebRTC which prevents IP leakage while using a VPN)
7. browser.send_pings = false (Prevents websites from tracking your clicks. Not the ultimate solution for this problem, but it helps)
8. network.IDN_show_punycode = true (Helps detecting fake websites by showing the punycode of websites. Here an example of how it can help: Impersonated Brave.com website pushes malware)
Obviously there are way more tweaks, but I think those are good starters.
Edit: Site isolation is now enabled by default in the new Firefox 94 version.