I had an extremely similar situation, albeit with a detached house.
we nearly cancelled our viewing after my wife saw the state of the house next door; overgrown garden, rotting wooden window frames, clearly empty.
But the house was perfect and the street was ultra nice and no other issues.
We asked a few neighbours and got the story that the next door owner had been elderly and struggled, then had to go into care and recently died, so it was going through probate.
It didn’t seem like it’d realistically affect the stricture of our new home, but it was certainly an eyesore, and the near guarantee of a developer buying and doing a big renovation was a big consideration considering we WFH quite a lot.
Ultimately we offered, a good amount under, eventually negotiated a bit, but got 30k off asking.
Sadly the vendors pulled their house off the market 3 weeks after accepting our offer, so we’re back looking now.
Another friend just completed on a 3 bed semi attached to an empty, run down property, with the owners currently struggling and failing to get planning permission for a big extension. It was missing some rendering and had a big hole through to see the floorboards / joints on the front of the house.
Again, my friend took the risk. The price was great (well under the market) for a big 3 bed with a garage in our area, he got it a bit under that, and the state of the house he got was really good. Easy choice.