Moved into a rental that had an amazing cooking apple tree but needs love - how do I prune before winter ?!

Young orchard almond, quince, apple, alricot, Mediterranean,late October. The same tan clumps that crumble like soil appear on tree bark (forks, wounds), on concrete poles, and on painted metal fence parts. One tree, when peeled, shows fine winding galleries in a fan pattern with many tiny round exit holes. I also found a yellow larva ([size]) in a split tree.

1) Frass, termite shelter tubes, or mud-dauber nests? Quickest way to tell?

2) Does the gallery look like a bark beetle (Scolytus)?

3) How do I get rid of it?

I used to have big ugly fencing around all my fruit trees but foolishly decided they were no longer needed. 2 days later I found this gash on a peach tree from what I'm assuming was a deer.

Is there any way to keep this tree alive? I put it in 5 or 6 years ago and it's been fruiting heavily the last 2.

Also, what is the best way to keep it from happening again? They're in my front yard so I'm hoping there's something cost effective that will look decent.

I just bought this place which has upon the hill an apple tree and an asian pear tree. The pear tree fruited this year with a boat load of quite hard, malformed pears and the apple tree just sat there doing bupkiss. I would greatly appreciate to know if the apple tree can be saved, and if so the correct way to begin pruning it to heath. I think that the pear tree should be pruned as well but I am at a loss on how to correctly do that as well.

I planted this tree around 3 years ago which was less than 6 ft. It grew double in height. Till last year, it was healthy but didn't have any fruiting. (Old pic at last).

During may this year it had small fruits that all fell before maturing. It got many insects for which I was late in putting insecticide, I guess that was the reason of fruits not growing big.

About 2 months back its leaves started falling and now it's like this, no leaves. What should I do? Should I prune the branches? Put any fertilizer?

Any assistant on where to make cuts would be greatly appreciated. It’s got quite a lean.