Glue makes lousy filler, especially for something you're going to use automotive paint on. Perhaps the epoxy will make a good base for automotive urethanes, but to be certain of compatibility, use products specifically designed as systems. If you do use epoxy, I would wait at least a couple of weeks for it to fully cure before working it at all.
For good results, follow proven procedures. Prime first and you'll see much more of what needs bodywork. Prime, fill sand. Prime, fill sand. You can use 120 for all initial work. On last primer coats move to 240 then 320. Prime again then sand with 400-600 for base color.
Only when your primed surface is prepped to perfection are you ready for base, then clear. Paint itself makes crappy filler and doesn't hide imperfections. Particularly true of metallics.
For filling small stuff like you pictured, polyester glazing works well. Think of it as finer grained body filler.