To add: I just tried these instructions mentioned by a previous user, and created an autostart.sh file via SSH.
Rebooted, still did not work. I also tried using chmod to give execute permissions to the file but it still did not work.
When I try to boot with the wifi adapter plugged in, coreelec boots but it gets stuck in the splash screen. When I unplug the adapter, it immediately resumes loading/booting into kodi.
Here are the logs, hoping someone can help and point me in the right direction.
Output when I run lsusb with the adapter connected:
Bus 002 Device 002: ID 05e3:0620 Genesys Logic, Inc. USB3.1 Hub
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 004: ID 0bda:1a2b Realtek Semiconductor Corp. RTL8188GU 802.11n WLAN Adapter (Driver CDROM Mode)
Bus 001 Device 002: ID 05e3:0610 Genesys Logic, Inc. Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub