Ranger is perfectly fine mechanically in 5e, it just feels bad to play. It’s the opposite of the Monk, that feels fun but performs poorly. The power of the Ranger mostly comes from the chasis being a really strong concept though, a ranged attacker with some spellcasting is just, a really good starting point. Decent utility spell options, OK damage options, fine ranged martial, it gels well. It isn’t as good as a Fighter at damage, or a Druid at magic, but it can do enough of both. There’s so much power budget used up there, the rest of the features got kind of gutted to make it work.

To be clear, in a cooperative experience like this, I would say the way it feels to play is much more important than the mechanical power. Monk and Ranger are both designed poorly, but the Ranger is probably the worst design. But many people take that to mean the weakest, and that’s not true at all. Ranger often outdamages Rogues, it’s solidly middlish, of the pack, maybe a little bit on the lower side, compared to the rest of the classes.