Do user testing and do it in a way that doesn't confirm bias!
There's a lot of 'fashionable' or 'trends' in design and UI and some of that is because big companies have found that it helps certain tools and actions. A simple example is, having AA+ accessible contrast colours on buttons, it helps mostly everyone because now people can see buttons clearly.
Sometimes trends are good but sometimes they are bad, for example, the trend of using lots of gradients, or carousels on webpages/apps might seem like its a good thing to have because...well...other do it! but the best way to find out if your users can use it is to do testing.
The conclusion is something that 'looks good/cool' might be completely un-useable. So focusing on what works first and build from there :)