I do mostly sign work in various woods and either paint or resin fill. The sanding sealer is absolutely the best way to go to prevent bleeding. I was using Miniwax poly matte satin and that worked well also.
For the resin fill, you have to sand if you are going flush to the wood surface, so I’ve been able to resin fill and then paint right after, wiping the paint off the resin.
I was using spray paint for some projects but recently switched to using an airbrush with Liquitex paints. Haven’t airbrushed since my college days but the finer control, less over spray, greater color choices and better control has lead me to leave the spray paint cans behind. Also, much easier to sand with light overspray (if any) using the airbrush.
Hope that helps.