I am in permanent AFib, but my symptoms are simple/easy compared to what you have. I take Metoprolol between 50 and 200 mg per day. I have troubling side effects only when at the 200 mg level, but nothing like your describe.
Have you tried calcium blockers? I am thinking about asking my cardiologist if I can try them as I think the BB is causing me to have "vivid" troubling dreams every night, no every time I sleep..I do wake up at least twice a night. I am not sure the BB is the cause, I may just be going nuts.
You high HR must be driven my something. Are you sure you do not still have AFib? Without BB my AFib drives my resting HR to about 130, with 50 mg - 100 mg per day my resting HR drops into the 80s. The heavy dose of 100 mg twice a day gets my HR into the 70s if I am really resting...not sure about what's going on when I sleep.
I too have had a mini maze that didn't hold. Mine was done during open heart surgery to repair my mitral valve. I have never had a ablation and my doctors say I'm "too" asymptomatic to take the risk associated with a left side (atrium) ablation.
Not much help, just trying to get the discussion moving with the little I have to offer.
Try to stay positive and remain optimistic.