Can I somehow attach a bashguard on top of largest chainring?
A lot of 104 BCD bashrings of the type that don't have cutouts for the crank arm would interfere with the crank arm by the time you spaced it out enough to go "on top" of the ring on a 1x crank. There's also the question of the spacers increasing the leverage that the spider tabs end up receiving, etc. 

If your crank has the ability to mount the ring on the other side of the tabs, you might try putting it there and measuring the chainline to see how bad it really is. Cranks where the stock chainline isn't actually perfect as a hedge against frame clearance issues is sadly common anyway, so it might be fine, and if it's borderline than it's probably only your smallest cog where it really matters anyway, which might be another thing to weigh. Crank-mounted bashguards do have a long history of encouraging people to ride crossgears; it's essentially what you're signing up for when you put one on a 2x.

Frame (ISCG) mounted ones have become way more popular. There's a certain logic to that in how once you're hitting stuff that's too much for the inherent strength of a steel chain on a 1x ring, maybe you don't want it hitting your cranks at all, and certainly not via extra long spaced-out chainring bolts.