I think the key is to make sure you have an audience mic set up to help with the sense of isolation. When I first got my ACS hearing protection, I had that same feeling, remote from everything in the breaks between songs. I loved the fact that I could hear myself much better because of the reduced levels, but couldn’t get over the feeling of being uninvolved between songs.
I’m dabbling more in the world of IEM and started like many of us with the KZ’s but I could never achieve total isolation with those, no matter what tips I used. I’m now using Sennheiser IE100’s on @warwickhunt’s recommendation, and the lower profile certainly suits my ears better, but the isolation still isn’t as good as a custom mould. So as a result, I generally only have my bass and a touch of vocals in my mix, and let the rest come through the lack of isolation. The upside is lower overall volume, and no ear fatigue. I’m sure my next step will be custom moulded in-ears but losing backline all together will need a serious FOH upgrade.