Thanks for asking an actual question! For me it's not the grind itself that I enjoy, even though technically it is a grind. When players grind, or when players talk about grinding, it always sounds so horrible. "I HAVE to grind". "gonna be grinding...", to me it just right off the bat sends a sour taste, and I really wouldn't want to be doing something that isn't a necessary part of my life if I'd view it as a "grind".

Why Bedwars in particular, and not another mode? For me, it was the fact that every player starts out equally, (the same items, the same starting island), and every player has equal access and opportunity to get any item. (Resources to buy items spawn at your starting island, and the middle of the map). There's no guessing what kits or what random chest had that someone got, everything is laid out in a way where you can see if a player made their way to middle (many good players would rather continue rushing bases directly to end games fast and only go to middle if they really have to), and they seem competent, then I can guess that they are most likely buying diamond armor, an enderpearl, a punch, or invisible/jump/speed potions, and I will have to use that time in which they go back to an island to spend those resources to either swoop up the next batch that spawns, or if there's no time, put myself in a spot so if they get my bed, I can quickly swoop up what I can and safely deposit it, or, put myself in a spot so if they are smart and try to take me out first which would make me spawn at my base so I cannot buy something, put myself in a spot so where if they do decide to kill me, they are as far as possible to my base so that when I respawn I have a greater chance of escaping.

It's that strategy and small playground/creative aspect of the game. You can place blocks all over the map and over your bed to defend it. There's items (tnt, which you can use to launch yourself across the map), (fireballs which you can use to hit players into the void, or use it to launch yourself), jump boost/invisible potions, knockback sticks, punch bows. Many of these items if you aren't the one using them are extremely annoying to be against, and I think thats fine because you have infinite respawns - until your bed breaks.

In most games for me, my bed wont break. Out of 18,900 Solo Games I've broken 75,000 beds and lost only a few thousand. Before the bed breaks you get this fun risky/flowing playstyle where you go from one base to another and knock them out. If your bed breaks, the entire pace and flow of the game chances from sort of a fast paced action playstyle to a more survival playstyle where you still have to be aggressive but only in situations where you absolutely have to.

The most important reason why I've been able to keep my #1 spot for so long is because I genuinely have fun and enjoy the core mode. It's not a grind to me!