The simplest solution would be a small clean sounding amplifier for your guitar (maybe on a chair, next to you). It dosen't need to be loud, its just your monitor ,then you DI that into the PA, for the out front sound.
Monitor systems are only as good as the people who operate them. If you keep it simple you dont get distracted and frustrated by the technology.
There are very high quality in ear monitor systems available, and others will be better qualified to advise you.
Myself I dont feel right wearing a "hearing aid" to perform.