is there a better or worse height for the seat to be at
Proper fit, although not an exact science as some would have you believe, is
essential-- extremely important for enjoying the bike and not injuring yourself-- and seat height is the most basic part of it. For best efficiency and strength and least risk of injury, your knee should be bent at approximately 15° when your foot is at the bottom of the turn in actual riding.
It sounds like you need to have someone who really knows fitting help you out. Many shops have a fitting service. It may cost $100 or even more, and take an hour or two. Besides measuring you all over and adjusting the seat up & down, forward & back, it may include swapping out the stem for a different length or angle, (hopefully the bars don't need swapping because that's a lot of labor!), and ideally even swapping out the crankarms for the right length. What I
don't like about the professional fitting services though is that they don't usually take into account things like age and past injuries-- just dimensions. Unfortunately the range of available crankarm lengths is extremely narrow anyway, and it's nearly impossible for some people, particlularly short ones, to get the right length. Professional fitting services also tend to start with the idea that the knee cap is supposed to be directly over the pedal spindle ("KCOPS" for short) when the crankarm is pointing straight forward, which I never agreed with and I see some in the industry don't either, as
this article from Keith Bontrager shows. I personally want my knees farther forward, ie, get the crankset farther back relative to the seat. That might be because I'm a spinner though.