Instagram has been putting a big emphasis on videos and Reels. If you want Instagram like it used to be, the web app is pretty close---and it can be "installed" like a regular app on Android and iPhone.
People have been increasingly frustrated with what the main Instagram Feed has become. What used to be a place for photos from your friends has turned into a lot of stuff you might not want to see. You can get to the "old" feed from the "Following" tab, but that's annoying to do every single time.
The Instagram web app acts essentially like the native app, but the feed is a lot cleaner. It even still has stories and messaging. There aren't nearly as many promoted Reels and sponsored posts. However, that could change at any time, so keep that in mind.
Both Android and iPhone allow you to "install" web apps to the home screen. This makes them easily launchable without going into the web browser. The first step is to go to Instagram.com on your phone.
This is possible with a number of browsers on Android, including Chrome, Edge, and Firefox. The process is very similar across all three.
Over on the iPhone and iPad (which Instagram notoriously does not have a tablet version), you're limited to adding websites to the home screen from Safari. Even if you don't use Safari as your primary browser, it's worth using for this feature.
It's a simple little trick, but it could improve your Instagram experience. The one thing you may miss out on is notifications. You could keep the standard Instagram app around for notifications and use the web app for casual scrolling.