It may help to inspect the plants after dark with a flashlight since several leaf-feeding insects feed at night so they can better hide from predators (or stay cooler). It's hard to determine what the culprit is if they are not caught in the act of chewing, since many insects can feed on foliage: many beetles, crickets, small grasshoppers and young katydids, earwigs, caterpillars, and more. Few remain on the plant while they are not eating, and hide elsewhere or fly away. Fortunately, despite creating a bit of an eyesore, they don't cause significant long-term damage to perennial plants. (Annuals might be more impacted.) For any pollinator-attracting plant or native host plant, we would not recommend treatment with an insecticide as such sprays would potentially harm other insects in the process.

Instead, you can hand pick (remove) any pest found; some beetles are quite easy to dispatch by knocking them off into a pan of soapy water to drown (the types of beetles that don't jump tend to just drop/fall off the plant instead of flying away as soon as they're disturbed, which makes collecting them fairly easy). Most leaf-feeding insects like those causing this kind of damage are not active all summer so will eventually disappear and the plants should outgrow (or at least tolerate) the damage.

Holes in rose foliage in particular could be from Japanese Beetle adults this time of year, but mainly are due to the feeding from one or more generations of Roseslug Sawfly larvae, a very common rose pest. (Despite "slug" in the name, these are insects that look a little like small caterpillars and tend to hide on the undersides of the foliage.) Although the sawfly feeding can create lots of holes, rose shrubs tend to tolerate it well and don't suffer much for the amount of temporary damage the sawflies can inflict. Here too, hand-picking is the most straightforward approach but a few lower-toxicity pesticide options exist if they persist, as mentioned on that linked page for sawflies.

On hostas, we tend to see damage from slugs/snails most often.

Miri

We agree that they appear to be Asiatic Garden Beetles. Their larvae (grubs) feed on turfgrass roots -- though not often badly enough that treatment of the lawn is needed -- so they will not be laying eggs on the other plants you found the adults on. Physical removal of the adults as they are found is the simplest approach to management, especially if you wish to avoid pesticide use, and no other intervention is needed as the plants should recover well enough on their own as long as their roots remain healthy.

Miri