I’ve been using the IEM active-ambient approach. My band can hit 105-110 dBA depending on venue/stage. Outdoor shows are generally easier. I start out with a really low stage volume though the IEM internal mics (supposedly -24dB according to IEM spec). I then add some keyboard wedge (time/gear permitting) as needed to get a sense of stage keyboard level. The wedge also adds a bit of body to the keys as opposed to monitoring with just IEMs. Then I add some keyboards to my IEM mix. Just enough to add some clarity but stay balanced. I control everything. Not a perfect system as it sometimes takes some hit/miss tweaking throughout the set to adjust for stage dynamics or keyboard settings. The system keeps me playing live somewhat, but admittedly, the overall experience is not ideal. I try to use them as electronic earplugs but if the stage mix is bad I just have to suck it up. Some gigs are better than others. Coming to terms that I’m getting too old for this.
Dave