valheim nexusmods is your best.
There are console commands that can do anything you want.

just a heads up. the game just got updated so most mods will be broken till they are updated.

There are mods for increased stack sizes, increased drop amount, and several ways to ether reduce weight of items or increase your carry weight using skills, bepinex allows you to change almost every singe variable of mods so if you feel one mod is to op you can reduce it.

Thunderstore is an alternative, tho its not very good, almost all mods are there as well and it manages mods for you and their dependencies, rather then having to manually install/uninstall them like on nexus.

Mod Organizer 2 got basic support for valheim about a month ago. Personally gonna swap to this one once it gets full support.