I've been using Vallejo and AK Interactive acrylics for years either brush painting or airbrushing.
As previouls correspondents have mentioned, for air brushing the standard Vallejo Model range requires thinning and a few drops of their Airbrush Flow Improver which is effect a retarder. The Vallejo Model Air range is formulated for airbrushing.
Also reduce the compressor air pressure setting for airbrushing acrylics, it does not need to be as high as for enamels or cellulose paints.
As
@michl080 says AK-interactive AK183 ultra Matte varnish is good and I also recommend this.
For brush painting I suggest a 'wet palette' as this keeps the paint moist during painting and prevents drying on the palette before your very eyes. A wet palette can easily be made from a tupperware (or similar) lid, a few layers of wet kitchen roll and a piece of greaseproof paper on top, onto which the paint is squirted. Mine is in a lidded plastic box with a wet sponge and a piece of greaseproof paper.
Before applying a primer to resin figures I would rinse them in IPA to degrease them.