Brave has an interesting approach where they have added core support for four key MV2 extensions to the core of the browser engine, bypassing MV3 entirely.
> Update: As of v1.81, we host the following Manifest V2 (MV2) extensions on Brave’s backend: AdGuard, uBO, uMatrix, NoScript. These extensions operate independently from the equivalent versions that are currently present on the Chrome Web Store, and have to be downloaded separately. Users can download and enable these 4 extensions from the brave://settings/extensions/v2 page.
> Update: As of v1.81, we host the following Manifest V2 (MV2) extensions on Brave’s backend: AdGuard, uBO, uMatrix, NoScript. These extensions operate independently from the equivalent versions that are currently present on the Chrome Web Store, and have to be downloaded separately. Users can download and enable these 4 extensions from the brave://settings/extensions/v2 page.
https://brave.com/blog/brave-shields-manifest-v3/