how would you recommend learning how to break/perform manuals more efficiently?

Performing manuals is a bit tricky, especially if you don't have experience using links from other fighting games. My best advice would be to start by trying to do light manuals after heavy linkers, since this is the largest timing window possible. Since the timing for performing manuals varies depending on which special move you are using as a linker (for example, doing a manual after Jago's wind kick linker is quite late, while doing it after Jago's laser sword linker is earlier), practicing light manual after heavy linker should give you a good sense of when the manual timing window is. After you get decently good at this, do the heavy linker again and simply try pressing a medium button instead of light. If your timing is good, it will just work automatically, because the timing window hasn't changed. If it doesn't work, you know that the medium move's slightly slower startup is the only difference, which means you're probably only 1 or 2 frames off, so try adjusting your timing very very slightly.
As for how to break manuals, it's really difficult to do on reaction, so the best advice I have is to just try to notice your opponent's patterns. If you're able to recognize the linker strength, you can narrow down your choices for guessing, but that might open you up to being locked out because the opponent tries an auto-double. A better idea is to try to break the linker before the manual, since it is usually easier to recognize the strength of linkers. If you notice that your opponent always does a certain manual after a certain linker, though, you can try to break it, although long term the game makes sure that you can't have as much success breaking manuals as you will by trying to break other parts of a combo. Practicing manuals yourself will gain you the same advantage over your opponent when you hit them, so they're definitely worth bringing into your game.