Not deer damage :-) And not insects either. Looks like apple anthracnose. It is pretty common in western WA and accounts for the majority of apple tree issues here.

To me it looks like freeze thaw cracks.

Freeze-thaw cracks are not likely to develop in this climate.....it just doesn't get that cold. I grow thin barked Japanese maples - notorious for developing freeze-thaw bark issues - in containers that remain outside all year long. They have never experienced this issue.

That link was great, thanks! That looks exactly like what I'm seeing.

Any idea if you can scrape back to healthy wood using a sharp sterilized pruning knife with this form of canker to save trunks/large branches?

I wonder if this is more of a younger tree issue. One thing about this region is that there are old, abandoned apple trees everywhere around here.

I've gone up and inspected some of these over the years. They haven't had any human intervention in possibly decades, yet continue to produce abundantly and never seem to have any major physiological issues, if any. Makes you think.

Generally, the suggestion is to remove heavily infected material by pruning. And it is common to both young and old trees. As a horticultural consutant, I travel around all over my area (3 counties) visiting clients and I encounter many very old venerable apple trees that have been growing for 50, 60, 70 or more years. Many have anthracnose and canker to varying degrees but are still able to live many more years and produce quite well. However, I would follow whatever cultural controls and spray regimes recommended for your area to minimize the issue.