Background: happily surfed with Brave under Sailfish OS 4. Updated to v4.1 and – WHAAM! 
– Brave consistently crashed after about 2 minutes usage. (Xperia XA2, Brave 1.5.5. Reinstall didn’t help).
Installing/using “Android stores” from the jolla Store didn’t work well: the Aptoide store only carried an old 1.5.5 Brave app (besides: the ads suck) and the F-Droid store failed to appear (jolla Store said it was installed but the app was nowhere to be seen).
Solution:
- (delete the Aptoide store, won’t be using this in future)
- dl the up-to-date F-Droid app from the web site (https://f-droid.org/en/)
- from within the F-Droid Store install the Aurora Store
- from within the Aurora Store install the Brave browser (v1.24.85)
Positive side-effects: the (bad) Aptoide store is gone. FOSS apps can be downloaded from the nice F-Droid store. Non-FOSS apps come directly from the source (Google Play) but through ~anonymous mediation of the Aurora Store client, a GPLv3 app (https://github.com/whyorean/AuroraStore#readme).