I’ve found a USB to 3.5mm dongle solution for iPad Pro 2018 owners (with a USB Hub)
Plugged this into my Aukey USB C hub and it actually works!
TROND External USB Audio Adapter Sound Card, with One 3.5mm Aux TRRS Jack for Integrated Audio Out & Microphone in https://www.amazon.com/dp/B07L56C28R/ref=cm_sw_r_cp_tai_chUfDbHPM6Q1V
Hey Apple! You can take away my headphone jack but you’ll never take away my dongle!!
Alternatively, get this
And plug in this, if you need more USB ports.
Anker 4-Port USB 3.0 Ultra Slim Data Hub for Macbook, Mac Pro/mini, iMac, Surface Pro, XPS, Notebook PC, USB Flash Drives, Mobile HDD, and More https://www.amazon.com/dp/B00XMD7KPU/ref=cm_sw_r_cp_tai_5rUfDb9VHTNDC
Which I can also confirm works.
Obviously this post is for people who need multiple ports. If you don’t, just get this.
USB-C to 3.5 mm Headphone Jack Adapter
Hope this helps someone.