Hi everyone,
The pinch welds on my 2008 Skoda Fabia Mk2 are too rusty to use, so I placed the jack stand where you can see in the photo. Could this spot have damaged anything, or was it unsafe for me to be under the car?
Thanks in advance!

Well, if the "beam" area did not cave in with the weight of the car, no, I believe you did not damage anything 😄

I would however haved moved the stand forward than you did, to have the car rest on the bolt of the subframe, which I believe is structurally more robust.