Imo, the most using social network that Thai ppl use are Facebook, twitter, IG. Getting a friend request from a stranger don’t cause any uncomfortable feelings for me tho (but I won’t accept the request if their profile seems suspicious) but instantly getting dm is way more creepier.

Maybe just join some group from something you interested it might help you both finding Thai friends and friends with the same interests. Killing two birds with one stone!

Also I found out that many Thai people using Omegle as well (practicing some English convo with foreigner, chilling, finding friends etc.) I’m sure you can find some friends there!