Hi Piyush:
Welcome the forum! You aren't alone in being displeased at Brave having taken the place of Firefox as the default browser offering in Zorin.
However:
Regarding privacy comparing Brave and Firefox:
Out of the box, Brave is generally more private than stock Firefox, but a well‑tuned Firefox can match or surpass it for some threat models.
Defaults: no tweaking
Brave: Blocks ads, trackers, many fingerprinting techniques, and does HTTPS upgrades by default via Shields, so your traffic is heavily filtered from first run.
Firefox: Enhanced Tracking Protection blocks many trackers and third‑party cookies, but it does not fully block ads or as much tracking unless you switch to Strict mode and/or add uBlock Origin.
Tracking, cookies, and fingerprinting
Brave: Uses “farbling” (fingerprint randomization) plus aggressive script and tracker blocking; it also uses more ephemeral storage patterns that reduce long‑term cross‑site tracking.​
Firefox: Has Total Cookie Protection, isolating cookies per site, and strong anti‑tracking lists, but relies more on cookie isolation than on blocking everything at the network level by default.
Data sent back to the vendor
Brave: Telemetry is opt‑in and designed to be privacy‑preserving; most installs send very little data home unless you enable specific features (rewards, sync, etc.).​
Firefox: Telemetry is on by default but can be disabled in settings; Mozilla is a non‑profit, but some people still prefer to turn this off for maximum privacy.
Advanced / power‑user privacy
Brave: Better if you want strong privacy with minimal effort and like having built‑in Tor windows and integrated ad/tracker blocking without extra add‑ons.
Firefox: Better if you want fine‑grained control (about:config, multi‑account containers, very strict cookie and storage policies) and are willing to tune settings and install extensions.
Practical takeaway
“Set and forget” user: Brave is usually more private by default.
“Tinker and harden” user: A carefully configured Firefox (Strict ETP, containers, uBlock Origin, hardened settings) can be at least as private, and you get engine diversity plus Mozilla’s non‑profit model if you care about that dimension.
Here's the link to the above, if you'd care to check the sources of the information:
https://www.perplexity.ai/search/is-brave-less-secure-because-i-ReIjvGu.Sz6IUzlGldKKKQ