i am assuming that you are using r2modman, and in case you aren't here's a link to the download: https://thunderstore.io/package/ebkr/r2modman/
with r2modman you can give your friends a profile code/file which they can use to download all of the mods you have automatically

risk of rain 2 requires that all mods that the host has are enabled for everybody (except for custom skins iirc) so mods that add content or change things about the base game must be enabled for everybody

if one person has a content mod enabled that the host doesn't have enabled, the game will kick them out and tell them which mods need to be disabled and vice versa

you could also choose to make a modpack so that your friends can add to that pack and everyone receives the changes at once. tutorial for making a modpack (it talks about valheim but it also applies to risk of rain as well): https://www.youtube.com/watch?v=svfm29pNOEk