You only have to clean the bores until any fouling has been removed and your patches or kitchen roll come out clean.
Based on my rifle experience this sounds excessive to me unless the gun has not been cleaned for a long time and has excessive fouling deposits.
The solvent needs to be left in to do its work to dissolve lead deposits and then can be helped by the bronze brush then push through with kitchen roll and repeat the solvent, leave, brush and push through until clean.
Blimey 4 parts of video amounting to about 30 minutes on cleaning a gun - I'd lose the will to live