Apart from that combat could be broken by spamming companion abilities once you unlocked them all, it didn't feel like there was any reason to use different combos than 2 or 3 that worked fine.
That right here is sus, TBH. Let me ask you:
- Did you play on Rhythm Master?
- Did you try to S-Rank levels?
If you did not, then this is pretty much the good ol' DMCV dilemma: game is so uninspired if you are not internally motivated—no bun intended—to style on your enemies, but styling comes out a bit more naturally on higher difficulties… except the typical non-action game fan will play a game once on normal difficulty and move on, so the real depth of the combat system is superfluous to almost everyone who played it.
Not that Hi-Fi Rush's combat is as deep or wide as DMCV, but it's more or less the same underlying concept here in terms of player experience.
In general, this type of action game requires some kind of intrinsic motivation—we could argue this is a design flaw, and I'd be inclined to agree to an extent; however, you're approaching this with way too much cynicism for no apparent reason, I think.
It just sounds like this game isn't for you, TBH, which's fine, it just doesn't make it a bad game. Also complaining about how limited the game is only to announce one sentence later you've been mashing the same two or three combos throughout the entire game kind of undercuts your criticism.
And let me be clear: your experience with the game is valid; I just think the logic behind your criticisms doesn't totally hold up.