Paragon can get you a lot of levels if you want to "retire" your sovereign and create a super hero.

I've gotten into the 40s with cheat mode.

If there is cap, there isn't enough experience in the game to hit it.

From experimenting in FE, I don't think there is a cap. Using the ctrl+p, I leveled a character high enough to have every single available ability (which, since you could get all the paths in FE, ended up somewhere like level 120), and I'm pretty sure I could keep going after that. Now, with LH, firstly you're going to max abilities out at a much lower level with only 1 path (I'd guess somewhere around 50ish), and I don't know whether the UI will let you go above that by taking an empty level. So, effective max level is probably either 50-ish or effectively nonexistent.