Don’t know what sillage tarp is; if it’s not compostable, I wouldn’t use it. I don’t think just covering would kill the grass in time. Maybe it would, but it seems like if grass can survive a longer time under snow cover, it would survive under a tarp. I don’t think anything would grow well just in compost and woodchips (I’ve heard some things do, but plants usually do need actual mineral soil). 4 inches of woodchips seems extreme for annual beds.
Could just till with a tiller or double-dig (hard work) and mix some compost in. Some grass will still probably come up, so will have to hoe every so often. After the first growing season, there’d be much less grass. And you can start using a no-till method.
For me. I think everything is physical, and there’s always a cause and effect. There is no magical non-physical consciousness. A combination of your genetics, experiences, and environment determine the “choices” you make/actions you take. Free will is an illusion, IMO.