In ear? vs. On/over ear? Your experience

I find over the ear better because they're just more comfortable, from my experience at least. I do wear in-ear ones, but only when I swim, got my hands on some waterproof headphones that are quite ok, some Platronics that I found reviewed online. If you are keen on in-ear, do some research first, or else you'll end up with pool sound quality.

Don't expect the same quality as with over the ear though, and from my point of view at least, don't expect the same comfort in the long run. But it's best to have some in-ear headphones too cause you never know when you'll need them, especially if you go for waterproof ones to wear them when you work out or do other activities that involve sweat and water. Here are some models worth checking out, maybe it helps:
https://popular.reviews/waterproof-headphones/

In ear monitors can sound as good as around the ear ones....you just have to pick the right pair.   In ears should be auditioned for your own comfort.....larger, smaller....to fit.

I've had 3 pairs of around ear phones and the most comfortable pair of those was from bose. Pretty good, but an issue for me is that the ears can heat up over time.  It can get rather warm.

I had a pair of in ears from Bose as well, their top of the line sports model from about 2012.  The sound just wasn't as good.  For me the best audio quality and still cool option was an on ear pair from Grado.  Though much cheaper it rivalled the sound from a pair of well respected Nad HP50 at about 1/2 the price, the SR125e.  The Grados are also open backed, which may help things not to warm up as much.

None of the pairs I've had would retail over $300, so maybe beyond that level things improve.  I would imagine that in ear models have come a long way since 2012, the industry has really been growing.

If you have 300$ or so to spend for in ears.....check the reviews for the Blessing 2.....you'll have to wait for about 6 months after ordering.

Questions:
1...Yes..
2..No soundstage or imaging..
3.No...