Genelec 8351b with 2x 7370 vs Sopra No2 vs Atc 50 ASL

I only have experience with Genelec  out of your list. They are great and extremely accurate monitors but are designed for sound engineers (who want to hear the bad as much as the good in a recording) so do nothing to flatter the recorded material. If you haven't spent a lot of time with studio monitors then I'd audition some first. I love mine but the guy who sold them to me hated them.

I can only offer my *subjective* opinion :) and add some considerations (you probably already know):First off, do try to listen to these speakers if you haven’t already, even if it’s not in your own space. You will get an experiental idea of each one's somic attributes.

1) Your listening your room is on the larger side, so you need speakers capable of large enough sound (SPL & FR) to fill that room, and offer you a good mid-to-far field listening experience

2) In view of the above, the 50 asl, nice though they are, fall short in the FR & domain and you’ll need a pair of subwoofers to complete the picture -- but they still won't fill that room IMO. If you like the ATC sound you might as well opt for the ATC 100, better still, the 150 if your budget stretches that far. If I were going for the ATC sound, the 150 would be my choice for that room.
3) The Genelecs are excellent for nearfield monitoring, which is what they are designed for. They go plenty loud with good technical characteristics -- but they are small speakers, made for smaller spaces; I’m afraid they will sound like whistles in your 45m2, even with the woofer complement. If you are looking for the monitor sound, you might consider Neumann: their bigger model (450? 420? something like that), might be more like it for your room. They sound subjectively good, albeit I listened to them years ago.

4) On paper, the Sopra II are the most plausible of your choices and, being passive, by far the most expensive. Having listened to them in a big room, I expect they will do the job for you -- and do it very well indeed if you like the Focal sound. They fill the stage with sound and create the illusion of a wide soundstage (wide dispersion characteristics). Mind you, the ones I heard were helped by a pair of subwoofers and were placed on the wide side (so few if any early sidewall reflections).
Problem: tyou need to shell out extra for amplification which makes them less value for money.
On the bright side, it will probably be easier to sell the Sopra than the others if and when that time comes.Enjoy the search!

My room is smaller than yours 4.25 meters x 5.5 meters and I sit about 2.5 meters from the speakers. I have the Genelec 8351b and 2 7350a subwoofers and I rarely turn the volume above .25 to .45 depending on the source. If I went for the Genelec you could try the 8361a or even the S360. Depends on how far you sit but the 8351b with subwoofers might be enough Genelec has a chart showing optimal listen distance and room size. 

https://www.genelec.com/correct-monitors