@unfa It's not quite undeniable and my low prior makes me still skeptical (because this kind of listening in, while technically possible, is challenging and does not provide much advantage over what G already has on people).

Some other possibilities:
* both you and your friend organized the meeting with G's knowledge, e.g. mails over gmail.
* the Jitsi instance you used was hosted in Denmark (someone already pointed out this language was actually Danish) and you accessed it with Chrome (or in another way that made G aware)
* same as above, but your friend sent you some link to a Dutch-adjecent webpage and you opened it in a way that made G aware
There are probably other ways like this, so you can try coming up with some yourself, since you know better what you did. ;p

Although, as I wrote above, this is technically possible, so I'm definitely not calling you a crank. It's just unlikely.