Central Asia or SE Asia as first "big" solo trip?

(For reference Im an 18 year old girl)

Currently planning my first "real" solo trip outside Europe. I've done a lot of solo travel but mostly within Europe (and a few east asian countries which were pretty guide dependent...), but honestly living Europe here makes that feel like it doesn't fully count, it's just so much easier when you already know how to navigate things.

I've covered pretty much all the Balkans, central and southern Europe at this point, so I really want something new.

I've wanted to do Central Asia for the longest time, mostly because the nature appeals to me way more than Southeast Asia. But I'm a bit nervous about going solo, English obvi isn't as widely spoken and the tourist infrastructure isn't as developed as in SEA. My budget is around €4k and I want to stretch it as far as possible.

My preferred accomdations are hostels and nature based stays, and Im most interested in hiking, beautiful nature, and cultural immersion. Parties are cool too but not a priority.

I'm particularly drawn to Uzbekistan, Kyrgyzstan, Mongolia and Nepal, but I wonder if SEA would just be the smarter "first real trip" choice. I'd also really like to avoid multi-day tours as much as possible.

Id think Im pretty travel and street smart but I just want to make sure I dont bite more than I can chew lol.

Id really aprecciate advice from people who have done one or both of the regions, especially as a young (brown) woman!

thank you so much! x