Not in the City of Pittsburgh - but I had kind of a similar incident as OP. One of my neighbors 2 doors down had their house up for sale (and had already moved out) and had one of those spinning roof vents that had a bearing go in it or something, and was this constant high-pitched whining that drove me and my dogs nuts any time the wind blew. (and for the record this is in Hopewell Township, right next to the airport that I listen to every day, so I'm not super sensitive to sound in general)

We didn't have contact info for the current owners, so I first reached out to the realtor who didn't respond.

Then reached out to my local township commissioners (CCing and including other neighbors with the same concerns, to not appear a Karen) and included video with sound. They sent someone out the next day to verify, and he stopped by for a friendly chat. They were able to bring to bear whatever township ordinance to basically contact the realtor and force the current owner into fixing it.

OP did the reasonable thing first - getting his landlord to talk to the restaurant owner first (ask nicely). But if it really is a nuisance, escalate up and hopefully someone will be able to bring some weight to bear.

Or... as I talked one of my neighbors out of... you could just climb up with a ladder and take care of it yourself. I don't recommend destruction of property though.

For the record btw I live in Hopewell township - near the airport. And the planes don't bother