First layer ragged/print head digging into plate?

I’ve had an A1 Mini for about two months now. A couple weeks ago, I print failed. The front cover was laying on the floor and the toolhead was wrapped in PLA. I took the toolhead apart and cleaned most of the filament from it. Since then, my prints have not been good. The first layer is ragged and it looks like the print head is digging into the plate. I tried changing a number of settings in Bambu Studio one at a time – plate temp, number of bottom layers, first layer filament speed and temp – none have resolved the problem. I’ve recalibrated a number of times. I tried raising the Z axis one step in the A1 Control/Extruder setting, but that resulted in the next print failing with a message that the print head is clogged. I’m beginning to think that the filament explosion damaged something, but I’m not sure what. I saw a similar post that a new extruder fixed that users problem.

I’ve been printing a small 10mm x 10mm x 5mm test cube on various locations on the build plate (Cool Plate Supertack). In the picture of the plate, you can see the scratch that appears on one edge of the cube, plus the residue that is left behind from the print. Any help to resolve this would be greatly appreciated!