newbie question - "oversummering" in zone 5

Hello! This is the first year I have grown amaryllis/hippeastrum. I live in zone 5 (southern WI). I have heard it is better to move the plants outside for the summer - first, is this true (I assume there may be some full-spectrum light benefits, but what about pests)? If so, is it best to keep them above-ground in pots, sink pots into the ground, or plant them directly in the ground (does it matter)? Finally: a few of my amaryllis have strange marks on the leaves, that may be evidence of some kind of plant virus. Does it matter whether I plant those in the same outdoor bed as other amaryllis without that problem?
Thank you for any input!
Laura