The only pest of consequence in my GH is spider mites. Those can be controlled with neem oil although I will admit I haven’t actually tried neem oil yet. I will this weekend.
Weeds are less with a weed barrier either inside or out.
What are way less in my GH are diseases of the tree and fruit. Things like PLC, stink bugs, and bacterial canker. The trees, leaves, and fruit in my greenhouse are basically pristine if one controls spider mites.
The other huge advantage of a GH is protection from freezes, hail, wind, rain, birds, coons, and similar.
On an area basis I’ve harvested at least 10x as much stone fruit, grapes, and figs in the GH vs outside.
It does take a well designed and properly equiped GH to gain all the advantages.