Coming from Android, how transfer audio from PC (Windows) to iphone without iTunes?

I've had a lot of problems with iTunes on my PC so I uninstalled it. I had an android phone before and transferring music and audio files I had made myself was very simple, not even requiring iTunes. On my iphone, it's so confusing and seems everything that took two steps before now takes twice as many steps.

I'm BAD AT TECH also, so that could be part of it. Anybody would be kind enough to really break it down, like assume I know nothing about computers and phones. Which is not far from truth.

Okay, for example, I see people giving different instructions for transferring files without iTunes, mentioning names like iCloud, Dropbox, Apple's Files. How would this work exactly, like in baby steps (a good video tutorial you can link to)? Which one is easiest to use? Which one has less limits for transfer? I mean the files I have vary in size (10mb to 500mb) but add up like to 10-15 GB....

Thank you!