First, nice username lol. And second, I’ve lost three monitors, a baby melinus, which I’m assuming is close to the size and build of your ackie, a little baby white throat monitor, and a 4 foot water monitor, which is probably quite a bit bigger than yours and as such was probably easier to find.
Melinus - he ran out of my room as I was cleaning his tank, and he escaped to somewhere else in the house. To find him, we decreased the temperature of our house and tried to basically freeze him out, and then put a heat light in each room aimed at the floor with a piece of slate under each one, hoping to draw him out onto them. We then put a few pinkies around each heat light to convince him to go eat them. We narrowed down his locations, turning over every bit of furniture in the house as we went. We found him a week later, on one of the slate tiles.
White throat - got out the same way the melinus did, but he’s a lot slower and less intelligent, so we were less stressed about him being lost. We did the same thing as we did for melinus, we found him the next day lol
Water monitor - we just put a plate of salmon in each room and we checked them each day and when we saw one had been eaten from we quartered off that room and searched for him. Found him a few days later
Hope any of this helps, and good luck finding your ackie!