Have I killed my linein input?

[JabberwockPL]

I wanted to do the hardware mod described here:
https://www.pschatzmann.ch/home/2021/12/15/the-ai-thinker-audiokit-audio-input-bug/

However, possibly I have ruined one of the caps, C18 that was supposed to move to C17 - these things are tiny! - as I no longer have a left mic input (only the right one works). I was not particularly concerned about this, as using the onboard mics was supposed to be only a temporary measure. The issue is that when I tried to use the linein, it is completely mute - now I am not sure whether the cap is required for the linein as well, whether I need to do something else to activate the linein or whether it is a separate issue with my board (v2.2 A436)?

[JabberwockPL]

It turns out I have the same problem as described here:
pschatzmann/arduino-audiokit#6

I.e. the jack splitter works with the computer but not with the board. It does not matter much, as I was using the headset only for testing, the actual input will be different.