Yeah. MV3 is a faster but less capable version.

With MV2, every request must be filtered with slow, JIT, garbage-collected JavaScript code. In MV3, filtering is handled by native browser code using the list provided by extensions. UserScripts could be used to modify the DOM, but that requires power users to manually enable it.

There is a limit on how large the list can be, depending on the browser.

that is theoretically true. but i switched to the v3-compatible ublock origin lite a year ago and i've noticed essentially no difference in the performance. all the ads are blocked, just like they were with the v2-compatible adblocker.