To be fair, you've been pushing Mythril pretty hard. People have been suspecting you're a mouthpiece for them and have been flagging your posts.
I haven't taken hard action yet, since I like giving folks a benefit of a doubt. But mostly I will close topics that are solely dedicated to an outside platform, like WT, since we had gotten many in the past.
People are free to make topics that compare and contrast multiple platforms at once, but if you push one platform too hard (especially if it's a smaller one), it will lead people to be suspicious of you.
As for letting your readers know you've migrated, the most efficient way is to announce it in your series episodes. There's no guarantee your readers even check out this forum, but they will check your content directly.