I don't know if I would characterize TikTok as 'authentic' first and foremost, but it's a platform where real people go to perform. When I scrolled TikTok, I would often get poorly-shot videos from average folks trying to put their spin on the day's joke format, or reacting to that day's outrage. It was junk food, but at least somewhat 'real'.

My Reels feed, on the other hand, is 100% bot drivel. It's all stolen viral videos by artificially-boosted accounts, and the comments appear to be fake comments that were 'paid for'. I assume there must be some sort of financial incentive to gaming the system this way.

The end result is that TikTok feels like scrolling through (attention-grabbing, reactionary) stuff by real people, and Reels feels like scrolling through some sort of bot wasteland.

I guess I should add that, due to its size, TikTok almost certainly also has a bot problem, but if it does it's not as clearly evident in a way that is detrimental to the platform.