So I heard you can create USER bots on TG, as in BOT-like bots but in USER accounts rather than BOT accounts.
I've been searching for ages, cannot find any libs related to MTProto with good documentation on how one actually goes about doing this.
I found the question: How do I use Telegram API without a bot?
however its for another language.
Please let me know if this is still possible, and if so, what libraries are useful for this - libraries that have docs preferably.
TdLib is what you looking for!
TDLib (Telegram Database Library) is a cross-platform, fully functional Telegram client. We designed it to help third-party developers create their own custom apps using the Telegram platform.
TdLib supports multiple languages and has a JSON interface for other languages. So don't worry about your programming language.
It even abstracts whether the internet is connected or not, downloads multiple files based on priority, and so on. I strongly suggest you use TdLib.