No coyotes here, that I've ever seen. But your post reminds me that we either have bear, or a very large man in the neighborhood who doesn't like me, by the evidence I infrequently find on my driveway and back yard.
They are both good products. They are not available for consumer purchase here, but different states have different laws. Please read all instructions carefully so you get the right dosage and apply them correctly.
You can spray a treatment such as Bora-care which has a low toxicity level compared to other treatments on all the wood. Not only does it soak in and last the life of the wood being a salt but it also helps against fungus. The chemical is disodium octaborate tetrahydrate. If pest control companies used this it would be a one time treatment. Fipronil is what you'd use for spot and ground treatments which is good for 10+ years when bound with soil.
I had the same problem on some timbers in my shop that I hewed out with a broad axe. I used Boracare ordered from Do it yourself
pest control. With a active infestation had to mix 1 to 1. I used a 4in. brush to apply. So far it has done the job.