Reading aux timecode with Premiere Pro
Premiere Pro does not currently read audio timecode, I wish it did as it would solve a lot of problems.   There are a couple options but either mean longer work flow and or costs money depending on your situation.

If you have Tentacle Sync hardware, you get a license for Tentacle Sync Studio for Mac or Tentacle Timecode Tool for PC which can overwrite your file embedding the audio timecode as file timecode.

Another paid software is LTC Convert from VideoToolShed. It does a much better job of converting timecode than the Tentacle Timecode Tool can do for PC (TTC tool will not covert 10-bit footage) using ALL-I codec on GH5 and the codec used for 10-bit on the Sony FS7 (and possibly the FS9).

The last option and this one is free, but means more workflow, Davinci Resolve (free version) will allow you to convert your audio timecode and then re-export the footage to use in Premiere Pro.

Me personally, I am going to spend the 135euros for LTC convert for the next big project I need to shoot. The demo version is free and you can convert one file at a time using the demo version.

Maybe someday, Adobe will get with the real world and be able to read audio timecode.