Black shows every bit of imperfection. That has a lot of imperfections. It also requires a lot of work for prep, sanding smooth, filling, priming, a 2-3 top coats. With the door on sawhorses you get the right look. A week or so of work.

Or just call a Pro. One in the 2-3K range for that level of project. Fine Paints of Europe experienced.

Is all the trim + doors flat like that? Get a good light weight orbital sander that can be attached to shop vac and sand with 100 or 150 grit, finishing with 220 grift. In theory a bonding primer will adhere to gloss but IMHO sanding should be done anyway esp on trim, doors or cabinet.... both to get rid of the gloss (for better adhesion) and to give you the smoothest, silkiest & most professional-looking paint job,

Thats assuming its not lead paint, you DONT want lead dust flying around! If any doubt, test the paint. Lead can be removed safely but not by sanding it off.