How can I fix my headphone jack/usb connections?

Generally I've been surprised at how easy it is to get replacement parts for all kinds of cell phones, and yours doesn't seem to be any exception. Searching for your particular model brings up quite a few places where you can get parts; the ones I tend to check first are Amazon, eBay and AliExpress.

For your phone, the USB charging port and headphone jack are on two separate assemblies, but both of them appear to be readily available. Here's one seller on AliExpress selling both of the parts you're looking for; the daughter card with the headphone jack is more expensive than it seems for similar parts on other phones, but a more extensive search may turn up something cheaper.

Original For ASUS ROG Phone 5 ROG 5S ZS673ks Type-C USB Charging Port Dock SIM Reader Card Slot Mic Signal Earphone Jack Board - AliExpress 509

Sorry to say I didn't run across any iFixit-style guides to replacing those parts, but you may have better luck searching YouTube for videos.

If you feel ambitious, take lots of pictures as you work and once you're done you can use them to create your own iFixit guide to those repairs. It's easy and fun, and will earn the appreciation of the repair community and especially those who come after you with the same problem.

Create a new Guide - iFixit

Good luck, and let us know how it all turns out!