If you know someone with an Android phone, might want to try various apps on that and see if it works.

You may be able to use a used Android phone in "airplane mode" as your "PC" for the ELM327. It will work just fine if you have a Wi-Fi internet connection for it. Can download apps from Google Play, etc.

I'm using a used Android phone for my new "CD Stereo". I have over 200 CD's on its SD card and use a wire plugged into the headphone jack which connects to my stereo amp with R/L RCA connections. Also internet radio. Bought it for $20 on Ebay and just never had it connected to the cell phone company.

Just be careful about what version of Android the working app needs.

So you can use Android and keep your iPhone too!