there was a thread where everyone had been promoting together but i just checked and that one got unlisted and hidden as well
the only other places I've known people to share or advertise commissions apart from where you've mentioned are DeviantArt and this website
https://artistsnclients.com/
I haven't got any knowledge on the place since I haven't used it but I'd found this blogpost sometime ago elaborating about it in pretty decent detail
the blogpost is very dated but it at least gives an idea of how things work there and i'm sure artistnclients has an about section that gives details as well
if you like i could retweet your tweet if you send it to me, not sure what it'd do but i'd like to help. hope you can figure something out as well