I've played a lot of WoW in the past, but I stopped in early legion. I started playing again when Dragonflight launched, but I stopped again just a few weeks ago - in part because I can't bring myself to grind anymore.
The endgame is fundamentally the same. You pvp, raid, and/or do M+, to grind for gear, and that's pretty much it. I don't do pvp, but I've heard the grind for pvp gear isn't bad. Raids and M+ are still quite grindy though, and for better or worse they're still pretty tightly coupled. If you want to play one at a high level, you'll have to participate in the other.
Personally I've never felt like recycled content was an issue in WoW, but since you brought it up, I'll mention that they're reusing old dungeons for M+ now. There are still 8 new dungeons, but each M+ season now uses 4 dungeons from the current expansion + 4 dungeons from an older expansion so that people aren't just spamming the same 8 dungeons for the entire expansion.
If you want a game that respects your time, my suggestion is to look elsewhere - especially if you're interested in raiding. They've made some progress in Dragonflight I think, but raiding at a not-casual level still takes way more time than it did pre-legion.
Personally I'm bored of it and have been for several expansions. I buy the xpac, play for a few weeks to check out end game, realize that it's the same boring grind with a lick of paint and shelve it again.
There's nothing inherently wrong with Wow and that's kind of the problem. By focusing on mass appeal the game has lost its soul. It's now about buying gold and paying for carries and nothing matters at all in it. I'm surprised that gdkp culture from classic hasn't fully killed traditional guild raiding in retail yet.
I played for awhile on launch after dropping off shadowlands HARD. I've been playing on and off since BC.
It's okay, probably my favorite expansion since pandaria. The first raid was pretty fun on heroic but still felt a little shallow compared to the classic cadre of raids (ICC, Ulduar, Sunwell). The mythics felt pretty well designed apart from some really iffy affixes for the first season, I dropped out before the new rotation so I can't attest to that.
Overall the game just feels way too grindy for me to get into anymore. Professions still feel useless and I don't get satisfaction out of pushing m+ to see my rating go up. It was wayyy better than shadowlands and BfA in my opinion, and if you have a good friendgroup / guild to do content with then it's a fun time.
Pushing m+ raiting lost its appeal for me when I realized how widespread paid gold carries are. The majority of people with good enough raiting that you'd want to party with barely know their class rotation. Raider.io is basically completely bullshit outside of the very top guilds and m+ teams in the world who earned it legitimately.
TL;DR - I'd say it's definitely decent (much better than Shadowlands) but the grind is always going to be there in WoW, I recommend skipping it and playing many other games instead.
I've played WoW on and off since beta and played the first season of Dragonflight. Flying was awesome, grinding is still a thing and like @rhokwar@[email protected] said if you want to do anything over normal raiding expect to be doing lots of M+. I don't like the timed aspect of M+, everyone is rushing and as a parent sometimes I have to stop the game and go take care of something, thus wasting 4 other people's time. I stopped playing WoW and have honestly really enjoyed just playing other games, when I was playing WoW that was all I had time for (grind grind grind) but now I've played and re-played games that I wouldn't have had time for. I started playing Diablo 4 and it definitely has grind going on but it's much easier to put down after playing for a little bit and the content is amazing. I played the new Starship Troopers FPS and while it's early release it was good fun and I'm looking forward to seeing what they do with that. I also got a Steam Deck and have had fun replaying South Park the stick of truth on the couch while hanging with the family.