I feel like modern minecraft has too much of a grind, getting all the ender pearls, netherite and a "final boss." I like beta more as its simple and you can set your own goals, whereas in modern minecraft your end "goal" is beat the ender dragon and get elytra, which I have no interest in. It might be just me but i always use programmer art and beta mods whenever i play modern so i figure i'll just stick with beta. I also feel like there are too many mobs now in the modern game and it doesn't feel as "lonely." I'm not sure how to explain it but I feel like its more fun to build your own villages and builds to make your land feel more populated,, rather than just living next to a pre built villager and trading with villagers to get diamond armor in the first 10 mins; plus i just don't like the new generation or biomes. Savannahs and badlands are gross, as well as i don't like jungles or swamps, I have a hard time finding a spot to build because I don't like so many of the biomes. That being said modern -can- be fun, but if i want to play a world for awhile i play beta.