Agitation. Any advice?

I agree with Grandma that there are medications to help. Some among us frown upon us, but for certain dementias they are crucial. Yes, there problems with medications. Firstly, finding the proper mix is a problem as you do not want to go from where you are to having someone drugged into a stupor, or stumbling and falling, thus leading to broken bones. At the least, it is easier to evaluate how medications are "working" in an at home setting than in a busier setting of extended care where attentions to fine detail are more divided. So speak to the doctor.
You may, realistically, be coming to a point where it is no longer safe to keep your loved one at home, and where placement in memory care is necessary. It is something to begin to think about.
I am sorry you are facing all this. I wish you the best of luck.

i had - and still have - the same with my loved one - constant pacing etc. i had read that dementia patients do this as when they are sitting it makes them focus more on their condition - or rather not understanding it - so the pacing kind of takes their mind of it - if that makes sense. either way i just go with the flow - with my loved one, we walk round, in then out, sit down, stand up, walk round. yes it's draining at times - he can do this for hours. i also buy things to help interact with him in other ways which he seems to enjoy. some days he doesn't pace as much. whilst it can be hard i try to look on the 'positive' side - he's getting exercise instead of sitting all day and whilst he's pacing i know his mind is 'active'. i wish you all the best anyway.

There are medications that will help with agitation, anxiety.
Discuss with his doctor what is going on.
If you can give a "meaningful" task to do that might redirect for a bit.
If there are Adult Day Programs that he could participate it that might help him redirect energy as well.
Lock up tools, ladders. There are covers that you can get for wall outlets so that cords can not be removed.

I'm assuming he has a medical diagnosis of dementia or some cognitive problem? If so he needs meds to address the agitation so talk to his doctor today.

As a secondary solution, you may need to come up with "purposeful tasks" to keep him busy and burn mental and physical energy: pairing a large tub of nuts and bolts; pairing a large laundry basket of colorful socks; putting together Duplo or Lego blocks using a simple instruction sheet; etc. You will of course have to "undo" the items at the end of each day (or ask a neighbor or friend to help you do this - easily done while watching tv).

I had my Aunt fold a large pile of kitchen towels, and sort poker chips by color (and then she proceded to arrangment them in interesting patterns because she was a graphic designer by trade).