It's not true that he's being looked at as a safety by "most" teams. A small handful of teams are looking at him that way. He's also made it clear to them that he's a linebacker, and I applaude that because there are too many bad coaches willing to play roulette with a player's career based on them purely trying to be the smartest guy in the room. Players have every right and reason to take control of their own fate and let coaches know what they're comfortable doing and what they know that they'll never really be comfortable doing.
You make Shaq Thompson a safety and you take away everything that is compelling about him, while simultaneously giving him a whole lot of snaps doing stuff you have no idea if he can be trusted to do. I don't care what people envision in their cute little fantasies, you make a guy a safety and he's going to end up in deep coverage at some point having to show range and trustability. We have zero idea whether Thompson can show those things in that situation.
If you envision Shaq Thompson as an experimental safety then you better not be drafting him until the late 3rd or 4th round, earliest.