My beginner proccesing skills, what do you think?

I think it looks good, great start on processing! Some suggestions and questions… 
Why did you choose HSO vs the Hubble SHO? It is a question of personal preference but was curious on your reason for it
Did you stretch with curves or HT or any other tools? I think you can get more details out still from this data with nuanced stretches in steps.
The background appears a little to dark, what does the historgram look like?

a little trick i do  to get color  stars.  S2 in red,S2 and o3 in green..both 50 % and O3 in blue.  Ha as luminance, the rest in pixinsight with colormask script.
greetings John

I'd say you're on the right track. Some people like the vivid colours, others, not so much. Star spikes for example are another point of contention. I personally think star spikes give an image character, although they are an artefact. I was also never really a fan of vivid narrowed colours, but the more images I produce, the more I like to try and be different. As well as art, I like to think of these images as chemical maps. The same way a infrared can be represented using colours going from dark blue (coldest), to red, then white (hottest). Keep up the good work, hopefully you'll be able to acquire your own data at some point.

I tried to improve the image. I unsaturated some colors, I used the Hubble pallet this time (SII-red Ha-green OIII-blue), I tried to reveal some more detail with more curves, I also tried to keep the brightest areas a little bit dimmer, and I preserved star colors. I'm only wondering if that blue glow on the bottom right corner is actual OIII or a processing mistake.

Hello,
in my modest astrophotography journey, all post-processing phase holds the 'highest' difficulty in term of degrees of freedom, because, in principle, we do not know which is the result we should approach. As an example, the nebulae colors are something extremely hard to consider as 'the exact result'.
Despite there are several techniques to emphasize nebulae chemical elements like HOO, SHO (as you also considered in your approach) which overcome the overall natural colors question, even with those particular post-processing choices different results can also be obtained by different astrophotographers, the latters being influenced (probably) by personal tastes but also by the environment 'surrounding' the data collected (our own setup, sky condition, acquisition technique…).
When I looked at your image I liked your overall result,  because you revealed a faint nebula like the Seagull in all its splendor. I also agree too, to do not be (as a general rule and as far as it is feasible) too much 'aggressive' in stretching signals especially if already strong (like your Ha),  so helping in maintaining your result as 'natural' as possibile so representing the nebulae delicacy.
All the best,
clear skies, Davide.