Is Roku OS falling behind the competition?

I've been a Roku user for 10 years, currently using a Roku Ultra. The UI hasn't really changed since 2013, which I used to love because it was simple. But now, it just feels dated. Plus, the lack of sideloading capacity (unlike Android TV) makes it useless for things like SmartTubeNext or custom IPTV apps. Are people finally abandoning Roku?