How do you record guitars at home without them sounding thin?

@Musician Less gain than you think is a good starting point. Double-tracked high-gain parts can get fizzy and small very quickly.

@Musician Record with the bass and drums in mind. A guitar tone that sounds huge alone may not be the one that works in the track.

@Musician Tight double tracking beats a giant single tone most of the time.

@Musician Before adding more plug-ins, I would check whether the part actually wants double tracking. Two genuinely separate performances panned apart usually create width more convincingly than duplicating one take, but not every arrangement needs it. A single guitar with the right midrange can sound larger than several layered parts competing for the same space.