Following trend is a good way to gain more views with TikTok shop. however, if you could build a strong audience. The story would be different, since you could introduce trend product and product that are suitable for your type of audience at the same time.
Both will have different factors for your audience to buy, but from my experience Trend product are good if you know how to persuade them to buy with your video idea. the other one is your audience, the more you could enage and understand with your audience, the higher chance that they will buy the product just because they like that story that you are telling them.