I grew up with home made tortillas and my mom would probably disinherit me if I added lard or something like that lol. So I’m very much in the camp of only salt, water, maseca and nothing else, but I think experimenting is always fun so that is up to you.
I would try making them a bit thicker, and like you said a warmer pan. Also, flip them sooner and then flip them back at the end if you want them to be toastier, that may help too.