That isn't alarmist, but almost all privacy features in Brave are already in Firefox as well. Looking at this page:
- Chromium customizations: Not necessary in Firefox
- Client-side encryption for Brave Sync: https://support.mozilla.org/en-US/kb/how-firefox-sync-keeps-...
- DeAMPing: I think AMP has been dead for a few years now
- Limiting network server calls: I think this is a bit tangential to privacy, limiting calls is generally good but it doesn't mean you're transmitting less information. Brave's post comparing different browsers' first startup network calls is from 2019, not sure how Firefox performs today.
- Query parameter filtering: https://firefox-source-docs.mozilla.org/toolkit/components/a...
- Better partitioning for better privacy: https://developer.mozilla.org/en-US/docs/Web/Privacy/State_P...
- Referrer policy improvements: https://blog.mozilla.org/security/2021/03/22/firefox-87-trim...
- Fine grained / temporary permissions API: This is nice, I don't think Firefox has this.
- Social media blocking: https://support.mozilla.org/en-US/kb/enhanced-tracking-prote...
- Bounce tracking protections: https://blog.mozilla.org/security/2020/08/04/firefox-79-incl...
- Limiting the life of Javascript: https://blog.mozilla.org/en/products/firefox/firefox-rolls-o.... Not explicitly mentioned but I believe Firefox does have this 7 day limit as well, in addition to other protections.
- Private windows with Tor: Firefox doesn't have built-in Tor integration, but the actual Tor Browser is built from Firefox.
I think Firefox also has one or two features that Brave does not, like Multi-Account Containers, and some paid services like https://relay.firefox.com/.