Using the OP's numbers.
91 hours blocks in 19 days = add 19 x 1.5 hours for pre and post flight duties = 28.5 hrs + 91 => 119.5 hrs blocks plus required duties.
19 days work @ 11 hrs/day => 209 duty hours
209 - 119.5 = 89.5 hours spent between flights on ground during duty day.
89.5 hours/55 sectors flown => average time between sectors ~1h35 which seems quite a long time/inefficient, especially as the average sector 91/55 is pretty much exactly the same?
So on the face of it, doable ... but doubtlessly, 91 hours 55 sectors/month is a lot and must be very tiring over time especially as you get older.
Checking my records, the most I ever did was 49 in a month on B737's back in 1993. I retired from a longhaul fleet where I averaged 845 hours & 94 sectors/year; ave length 9 hrs.- much more my cup of tea.
Bon chance!