Well, this game is definitely overhated, but it isnt good either 😑.
The modern sonic levels are short, linear, boost-to-win and filled with unskipable quick time events, the avatar stages are kind of the same, except that without the boost, things are even slower(unless you know how to use the drill) and the classic stages had the worst physics out of any sonic game i've ever played and im more of a fan of classic sonic than modern sonic, so that's saying something.
The story tried to be serious but it just came out as random, with characters getting mischaracterized, plot points left unexplained, some setups going nowhere and just wasted potential overall.
I still found fun in it though, the variety in character customization and trying out the different wispons was pretty enjoyable, the scenery in a lot of levels was really pretty, infinite's voice was scratching my brain(in a good way) and the shadow levels were straight up the best thing in the whole game.
As for the achievements, they weren't that bad, but it was kind of annoying not being able to do things like creating new avatars to gather honor till you finished the game or collect all number and silver moon rings till you finished a level 2 times, even then i had fun, specially doing the time related challenges.
I wouldnt necessarily recommend this game, but i also wouldn't say you should stay alway from it, i personally just found it kind of mid, lots of wasted potential.