Well, I'm not the expert on scanning iOS but I am pretty sure that Lansweeper gets the user info for that stuff only if the devices are enrolled in InTune for management.
**This is not supported by support, so insert the 'you're on your own, don't screw up your database and don't say we didn't warn you' warning here - which is what they generally tell me***
What I do is make an API call to the MDM and pull information from it that Lansweeper doesn't get out-of-the-box - particularly user assignments. Now - Lansweeper has custom fields, but only 20 of them. Seems like a lot, until you do a lot of stuff like what I'm suggesting. So, if I don't want to sacrifice one of those precious 20 fields, I will sneak the info in somewhere else on the asset page - for example, the 'description' field.
Here's an example pulled from JAMF - but I have the group it's in, versus the user - but you get the point.

That's the easiest way to do it, but you won't get to drill down to the active directory user like you would be able to if it were in InTune - without some heavy duty SQL writing (based on AD Object GUID probably) which is beyond my skill and I'd have to buy the DBA a drink or something... but you could at least have a report and add that column to see the user