Is my room doomed? Pic

Enzo, sounds like you're making progress. Congratulations. I did read above a suggestion to add a carpet to the floor. Have you tried this? I have one and added a second pad underneath it. This reduced floor reflections resulting in a cleaner, more accurate sound. I suppose treating the ceiling would help, though it is not as easy and aesthetics come in, but these two additions may effect soundstage hight.

Good on 'ya for trying various things and noting the differences. Measuring the frequency response / SPL (dB) is also important for trying different things so you have a record of the sound for each setup variation.

You wrote: "the biggest issues are probably 1) soundstage height is a bit too low and 2) I still want more overall bloom in the soundstage (envelopment from up down left right)."

1) Sound stage height too low: Try sitting on the floor ;) Seriously, put a rug on the floor to kill flutter echo between floor and ceiling and see if that does anything for soundstage height. Otherwise, keep the wood floor bare and raise the front of the speakers (or lower the back of the speakers) with the thinking that just as side wall 1st reflections that aren't absorbed or diffused help with widening the apparent sound source and increase listener envelopement, so too should it work in the vertical domain. Raising the front of the speaker's will put more HF energy up to the speaker and subtly call your attention to the height. However, it's not likely to be as drastic a change as lateral reflections because we hear more effectively latteraly rather than vertically due to our ear positioning on our heads. Lastly, you could add white RPG Skylines (see my system or others that use it) to gauge if this impacts the height. Personally I didn't find it added much but that could be due to my speaker's vertical dispersion pattern, or lack thereof or the sheer angle that the 1st reflection is at given I sit near field.

2) Soundstage bloom and envelopment is a funtion of indirect sound resulting from reflections from bare or diffused surfaces, and mostly from side walls which you lack. Have you considered rotating your system 90 degrees like I mentioned previously? I know it's a lot of work - ugh.

I would recommend trying "get better sound" by jim smith. he's very helpful on room setup.

also, very good you are thinking careful about position. I hate "best speaker" discussions here because room position is so important to sound.

getting rid of TV in the middle will help with bloom. it is good you are focusing on this, also.

I don't know enough about these speakers, but I do know you can shift soundstage of planar up and down by tilting them. maybe these too? also, adjust toe-in for sound stage and imaging.

There is interplay between how much you can get speakers to play the room and how much you accept defeat and try to isolate speaker sound from room. I find I get best result if I have a lot of toe in and send HF directly to ears. Sweet spot is small, off axis listening is not great, but I get densest tone and bloom given limitations of my own system.

Having no side walls is a blessing. You can set up a classic LEDE configuration by moving the TV screen and putting up something very dead on the wall between the speakers. Maybe a large mattress covered by a nice tapestry.
Best,
Peter

Does anyone know how to get more soundstage height?

This is going to sound simple minded, but the best staging height I ever got was when I had a room with 14 foot ceilings. Now, you can't exactly go raising your ceiling unless you buy the place above yours and demo it, but maybe you can get the effects with dampening and diffusion. Just like everyone recommended a rug for your floor to ease reflections, give a look into an acoustic treatment for the ceiling - even the standard "popcorn" ceilings have made a difference for me (though they can look a little tacky in a clean, modern design such as your home).