I have some good new for you today! Custom Campaigns are coming to Warcraft III Reforged.
Warcraft 3 Reforged Custom Campaigns
Right now there is no option to play custom campaigns in Warcraft III Reforged. But when i reported a bug about campaign progression not sync between 2 devices i also asked about the custom campaigns. Below is the response from Blizzard:
Thanks for getting in touch with us about your portrait problems today, and also Custom Campaigns!
The issue at the moment is that WC3 Reforged does not currently have data transfer available, so your progress will only be available on the PC you performed it on.
As for Custom Campaigns, we’re currently Reforging those to be even better than they were before, and they’ll be introduced back into the game soon.
I hope you’re still able to enjoy this epic experience, and have a fantastic weekend!
So at least we now know that custom campaigns are coming back “soon”.