You can probably sell the IG and FB pages if they have good engagement rates?
Direct messaging and pm'ing people isn't the best strategy as it's spammy and people. hate. spam.
Are you still a designer? From the sounds of your post, it sounds like you are, to be blunt, almost wasting time building these audiences that don't have anything to do with being a designer and selling your work, unless of course your wedding Instagram accounts and the accounts you're building have your designs as content? Or are you pivoting and you want to focus on building accounts and monetizing them instead of designing?
You need to put some spend behind your FB posts as well, and have very specific targeting (but not too specific that FB flags it as too specific lol).
You also want there to be a clear CTA for almost every post. With audiences that large, you're leaving money on the table if you don't convert them or make them take a specific action.
