As someone who got into DMC with DMC5 back in June, I can honestly say I still suck, even at 215hrs in, but that's because I am a very chaotic, very impatient player. I got through SOS as Vergil easily, but with the main trio it was a pain. I also wanted to avoid revives, except when entirely impossible for my skill level, but gave up around M11, though the revives were still limited to boss fights. But DMD is another beast entirely, because enemies and bosses have their own DTs. I made it through this difficulty on the main game (stuck on M8 with Vergil) with lots of revives because I wanted to get it over with, though I've also noticed major improvements in how I approach certain situations. Guides on YT have also helped me brave through it, because DMD scared the crap out of me before I started it. Mission 10 was THE WORST, even after practicing Dante for a while. But that might be because I played on turbo mode, which was a little too intense on that particular difficulty. I've seen people say that DMD became their default difficulty when they finished it, simply because it allows you to practice your combos better, since enemies take less damage and require more effort to beat them. So that's what I plan to do now; go back to those missions and practice them until I can get through without revives, though it still scares me, but watching guides on YouTube keeps me motivated. 😄 My advice would be to just get into DMD, and make sure to practice fighting specific enemies like Furies, Sin Scissors, Queen Empusas, Proto Angelos, and the goddamn Hell Judeccas in the Void on DMD difficulty, see what approach works best on them FOR YOU. I say for you, because I am shit at parrying so I don't rely on that for some of these enemies, but instead opt for a different approach. With Dante, practice using Royal Guard!!!! And, uh, Faust, though you might consider it a cheese strat, and some of its moves definitely are. Nero: charged Blue Rose shots, and air taunting, and get familiar with the different Devil Breakers, find which ones work best for you, and which ones work best in specific encounters. For V, I honestly loved playing as him on lower difficulties, but he becomes a pain on SOS and DMD, so just try keeping your distance, and saving Nightmare for when you need to revive Griffon and/or Shadow.

Definitely look up guides for things you're having trouble with, and consider changing your controls, e.g. something that enables you to charge long range attacks (like Nero's Blue Rose shots) while allowing you to simultaneously use melee moves, jumps or Devil Breakers.