What you're describing is something I see a lot of people commenting about on social media. Facebook and Instagram are still platforms with a lot of reach, but competition has tripled over the last five years, which explains why costs are going up and returns are going down. It's not that they stop working, it's that now you have to be more strategic. Before you could launch a generic campaign and it would work; now you need much finer segmentation, constant creativity, and frankly, patience to test things out. If you've been there for five years, you already know the platform, so I wouldn't write it off completely, but it would make sense to diversify.
TikTok and Pinterest can be interesting for clothing depending on your target audience. TikTok especially if you're going after a younger audience, because the cost per click is still lower than on Meta. Google Shopping is also really worth it if you're not using it already, because people actively searching for clothes on Google have clear purchase intent. What I would do is cut your Facebook budget down to the minimum to keep your current customers, and put money into one or two new platforms for a couple of months to compare results directly.
One tip: don't just look at cost per click, but actual cost per conversion. Sometimes it seems like Facebook is more expensive, but if your profit margin is good, it can still be profitable if you manage to optimize your campaigns well. The problem a lot of times is that the creatives get old and Meta penalizes that, so if you're not changing your content regularly, performance naturally goes down.