What you described is a “ruined orgasm”, or an “abandoned orgasm”, and I would say that you could get the stamina benefits from edging as long as you don’t feel the psychological/physical contractions of the orgasm. In fact, if you can work on relaxing your PC muscle and allowing a full cum load to just dribble out of your dick, you’ll have increased your abilities even further.
The general principle is separation. Edging allows you to separate the mental lock between stimulation and orgasm/climax. One form would be to stimulate yourself until just before your orgasm or climax begins, and then back down. Repeat for 30 minutes or so, and then just stop. Don’t come immediately after an edging session, that defeats the point.
If you wanted a more advanced/multi-orgasmic result, then you can separate your orgasm from your climax by giving yourself a ruined/abandoned orgasm. Edge up to your climax, make sure to completely relax your PC muscle, and then stroke yourself a few more times until you’re past the PONR, and then RELEASE YOUR DICK! Take your hand off, stop all stimulation, and concentrate on keeping your PC muscle relaxed - don’t let it contract. If it contracts, you’ll have a full orgasm, and you will have reinforced the opposite result than what you desire. If you manage to keep it relaxed, you’ll ejaculate but you won’t orgasm.
Now when you’re having sex, you probably won’t want to ejaculate without orgasming, although this is one way to use your new found skill. It will work, that is it will allow you to continue having sex even though you have already ejaculated, however this is normally too messy and most men would prefer the feeling of the orgasm without the ejaculation. The main benefit will be from practicing this relaxation of the PC muscle is to help separate the physical lock between orgasm and ejaculation, and allow you to progress onto clenching the PC muscle so that you have an orgasm but do not ejaculate. It’s much easier to relax the PC muscle and give yourself an “abandoned” orgasm, so that’s normally a good place to start.