Then they should be better. Nexus' monopoly is like steam's. They got it by just making a product that isn't a major pain to work with. (Okay all Bethesda modding is always a major pain but nexus has made it as tolerqble as it has been so far)

Moddb?

Moddb was mentioned. Another good one is thunderstore. It all depends on the game though. Valheim (and several other units based games) is very active on both Nexus and thunderstore, stalker games tend to be moddb, &c. Nexus tends to be the main one for most games though.

I mostly like Nexus (paid member), but I share the concern about it being the only game in town for most games. Nexus is heaps better as a site than both moddb and thunderstore ime, but the lack of real alternatives is putting way too many eggs in the same basket.

They are also known to ban mods they don't like.

Like it or not, it is golden standard. Streamlined like hell and makes getting into modding a childs play, both visually and mechanically. Only when you start going deep into mods does Vortex shit a brick.

They really should add option of unlocking manual order of mods and for me, that would be it. Sadly last I heard they said no.

Edit: Also you still can bypass automatic load order by entering manual value for mod, they do have that option...but I found it's behaving kinda quirky, so still would prefer simple drag and drop. Also uses 16 base which for most users will be offputting.

Also also you can add reqs to load something after something else, but that works as long as first mod doesn't need special place.

Yeah all of that is valid, but it doesn't really justify putting a mod on a platform that's objectively worse for modding and making a large portion of your users have an objectively worse time installing and managing all their mods. I would love for gog to step up and make a modding platform (and specifically mod manager) even close to the quality of nexus' but they haven't yet.