Basically for context:
DMC1 came at a time when shit like Castlevania 64 was all that we had for 3D action games. So if you play it and think "wow this is kinda garbo" just stick with it. Remember that the game's combos primarily center around pausing with your melee attacks.
DMC2 is a trainwreck in terms of production and product. It was handed off to a different team than Hideki Kamiya, who was salty about it up until leaving Capcom, and Itsuno was brought on to try and salvage the shit that wasn't working but there was only so much he could do so late into production.
Itsuno's then like "Well fuck that sucked. Hey can I get another chance at this thing?" and Capcom okayed it and we got DMC3 which is probably the best game in the series and is like, to every Platinum game what Dark Souls is to 'souls' games.
DMC4 sadly had a rushed production cycle to get it out on the new generation of consoles. The game basically repeats itself in the second half and it shows.
DmC meanwhile is divisive for a lot of reasons. In terms of gameplay it's fine, but the writing is more of an edgy Garth Ennis type thing than the campy anime bullshit we're use to and it ironically suffers for trying to give the fans what they want. Donte started out as an angsty loner which could've worked for his character arc but then they made him more like regular Dante which just made him a jackass.
Play DmC if you like. I'd honestly recommend it over DMC2 if only cause DMC2 is just boring. But yea it's disliked for a number of reasons.Also there's the fact the game's writer called OG Dante 'gay' as an insult in the same way your highschool bully calls you gay