How to keep dog from jumping on bannister/wall?

Hey there!

I'm in a bit of a strange situation -- because of Covid, I've had to move into a place where someone else also has a dog. Thankfully there are two floors and I'm able to keep my dog restricted to the basement/upper stairs via a babygate at the top of the stairs (the other dog is territorial and does not get along well with him in the same area, they're completely friendly outside and play together, but the house is her house, which is entirely understandable.)

This isn't a permanent place, this is just for the duration of Covid, so this isn't a situation where I'm going to try and fix the other dog's territorial issues since, again, I'm just a temporary person here.

The big issue here is that my dog will hop up on the wall that blocks the stairs from the hallway. There's a seven-foot 'landing platform' at the top of the stairs with a counter wall on one side. Because he can't see me when I'm upstairs, or he can't see the other people here, he will jump up to put his paws on the counter and peer over it. This is becoming a huge issue because he will rake his claws against the paint or gauge into the wall itself. We've tried scolding, we've tried telling him to go in his crate when it happens, we've tried to put the gate at the base of the stairs instead (he cries and cries and cries, then will proceed to bark because he's anxious and confused,) we've tried putting velcro on the section he puts his paws on but nothing.

I'm not sure if there's anything I can put on the wall itself to deter him from putting his paws on it, right now we just need some ideas on what to do to make him not want to hop up, and then we can deal with his anxiety over being separated from the other people in the house.

Please keep in mind that I'm with my family, it's not feasible for me to just stay on the lower floor with him 24/7, and I also work 40 hours a week/10 hours a day/4 days a week, so it's not just me that is looking after stopping him from this. He used to be my mom's dog, and is still very attached to her, and so gets extremely upset and confused when he can't be in the same room or is blocked by the baby gate.

We can mount pretty much anything on the wall, but we just need an idea of what could possibly work. If anyone has any advice on that front we'd all be super grateful. This is an extremely different situation for him and not one that he'll encounter again once I move.