I built planetiler (https://github.com/onthegomap/planetiler) for this purpose. The output up to z14 is ~80gb and depending on how big of a machine you have it takes from 30 minutes up to a few hours - no DB required, just java or docker. If you are only going to z11-12, it should be quite a bit faster/smaller.

Brandon from Protomaps is also helping add pmtiles output natively to planetiler, so you won't need a conversion step afterwards!