A userscript to open Reddit links in the Apollo app on iPhone. Works with sideloaded apollo as well.
Safari extension to run user script (free): https://apps.apple.com/us/app/userscripts/id1463298887
Userscript code: Open In Apollo Userscript
Install the free open source app Userscripts
Launch the app and choose path for scripts
Enable userscripts on your iPhone in Settings > Safari > Extensions and allow access to sites
On iPhone/iPad tap to see the open the code Open In Apollo Userscript
Tap Aa in safari and Tap Userscripts
Install the detected Userscript.
Open any reddit link in Safari, you should see a pop up asking if you want to "Open this page in Apollo"
Tested on iOS 16.7.2