We are seeing more small/tiny bees/wasps than we remember.

Flies are completely natural so no need to trap.......unless you feel the need :-) I have no issues with them outside but draw the line when they move indoors, so screen all openings.

Flies can be attracted by various scents and/or rotting materials around. Using very smelly ferts like fish emulsion can attract them, as will an open compost or uncollected pet waste. And there is always the possibility of a dead animal (squirrel, rat, mouse, etc.) somewhere on the property.

Flies are a broad group. Are yours like house flies, or the common blue- and green-bottle flies similar in size and shape to house flies? Any scat in the yard (dog, possum, etc.)?

Hover flies are beneficial.

Biting and fruit flies are the real pests.

The white butterflies are Cabbage Whites and their caterpillars eat cabbage and other similar vegetable leaves, and nasturtiums.