Some of these threads genuinely make me wonder if some of the posters have even been in an office before. From the public to nonprofit sector and everything in between it’s been atypical to see an office devoid of personal items. My current boss actually was quite weirded out by how little personal items I brought in initial and he strongly encouraged me to bring in photos and other things to make the office feel more personalized.
To the topic at hand, I’d probably go with a shadow box due to the dust factor. It also gives you the ability to match the framing material to other items in the office to create a nice cohesive feel.