Hey Jayd118,
We understand you're having issues opening Safari links within their respective apps. We'd be happy to help out.
You mentioned that it takes you to the App Store where you then select to open the already installed app, instead of it going straight to the app. There seems to be some kind of disconnect where your iPhone isn't recognizing right away that these apps are already installed. With that being the case, we'd suggest uninstalling and reinstalling any affected app.
For help with doing so, please review: Redownload apps and games from Apple - Apple Support
How to redownload apps on iPhone, iPad, or iPod touch
1. Open the App Store app.
2. Tap the sign-in button or your photo at the top of the screen.
3. Tap Purchased.
4. If you use Family Sharing, tap My Purchases or choose a family member’s name to see content that they purchased.
5. Tap "Not on this [device]."
6. Find the app that you want to download, then tap the download button .
We hope this helps out.
Take care!