How about an espaliered plant (the product of regular and judicious pruning) or a simple trellis with a decorative vine and small shrubs?

Pull up the pavers and plant some 6" tall shrubs.

I agree that a planter and trellis would work well and set forward of the wall so no chance of damage'

Maybe just use it as a backdrop and plant in front of it? This is Fineline buckthorn (restricted in some areas, so check before using) and black mondo grass. (The roof is the worst part of the garage; maybe they'll re-roof soon!)

Not sure but the firepit suggests that it might be a nice spot to hang a screen for outdoor movie projector. I love outdoor movies. Get some Simo bluetooth speakers and everyone has a speaker next to them so it doesn't have to be loud outdoors.

https://www.pangissimostudio.com/?gclid=Cj0KCQjwk7ugBhDIARIsAGuvgPbDxGWmlclM8R-Z6KuqB6u9IGPjv6BnTZV3eOBCRtpBKhrnDjcQJE0aAlMdEALw_wcB

Once you beautify the wall area perhaps a little table and chairs to enjoy outdoor meals from the grill…some outdoor lights for evening drinks in the summer? A tiny decorative gazebo area for privacy?

Decorative shade screen panels are the way to go. They are movable and will elevate the look and no maintenance! I actually bought mine on Houzz to dress up our backyard block wall and get so many compliments! There a number of patterns and colors.

Terri
Terri Brien Interiors

Whatever you do, don't put something so close to it such that they can't get to it to paint it when it needs it. Peeling paint will look worse than how it looks now.

Plant some natives, not buckthorn, which is a thug. You can get ninebarks, elderberries and thujas that are columnar.

Have you asked the neighbor about it? I created a nice planting on joint property with one neighbor. I came up with a plan and reviewed it with them. They said ok. They really liked it as it grew. They helped me care for it until one got sick. I worked alone a couple years. Now one helps again. We built a friendship over the shared space.

You guys never disappoint! I love these ideas and yes the neighbor is a good friend and creative partner on the project :) I’ll be sure to post the results!

I might want to do something that doesn't take up any space from your small patio area there. Would they let you do something like this?

I also saw this 3 panel screen at Costco