If you want to share information and ideas related to fashion then Twitter could be a great place to start. You could also use Twitter to engage with conversations being started by other users, which can be useful in building brand awareness within the fashion community.
However, if you’re going to posting videos/photos then you’ll probably want to try TikTok and continue using Instagram.
My personal advice would be to keep doing what you’re doing. If you’ve made 10-20 pages and none of them worked the way you wanted them to, start looking for reasons why they didn’t work. Get specific about what you could’ve done better, and then try again. Also, look at some of the posts that did work, find ways to build off of those ideas. It might take 100 attempts to get the result you want.
Switching platforms likely isn’t going to be a quick and easy fix. A brand needs to offer some type of unique value in order to stand out and be worth the time and energy of customers/followers. Figure out what unique value you can provide and then use the platform(s) that are the best tools for helping you deliver that value.