What is the upper deck decking material you used? What is the finish applied to it? The sides with the board & baton need ventilation or no finish will stay adhered to the top deck. It has to have air flow.

Trex. Two doors on either side and one small one under the door. plus once landscaping goes in, we are placing small vents on each side.

you can see the door under the patio where there is cover.

Some kind of

I hate AI images. Keeping any yews or box trimmed that small will take constant pruning. You should put a nice, bushy shrub in the corner in the last picture. But, what shrub depends on your zone, sun/shade and soil. Soil can often be a function of nearest city.

How much do you like to garden? You could put a little garden in that corner, instead.

More with flower bed with or without pathway.