Weird layer issues in my print

I've got these weird gaps appearing in my layers, as well as gaps in the top layer. Any idea why? (Image of calibration cube print in attachments)Ender 3 V2 Neo, PrusaSlicer, PLA. I've printed fine on this for several months and just replaced the hotend internals after wrecking the previous one. Running at 220 degrees - I have tried lower as I usually print slightly lower but this was the best attempt so far (bed 60C, and I've tuned PID).I've calibrated esteps. I don't think it's underextrusion as I've tried running a cube with a higher extrusion multiplier (1.2) which doesn't fix the problem and causes typical overextrusion symptoms.I've got 5 top layers in the slicer and fairly default settings as I reset the profile to default to see if the problem was caused by me setting a weird slicer setting.Filament is not tangled, nozzle is not clogged (as far as I am aware), bed is levelled with ABL and first layer is fine and solid, unlike the top layer. The extruder tension is good too as the marks on the filament show a firm grip but not grinding.Infill is at 10% adaptive cubic - which usually seems to work fine. I don't suspect filament hydration as it's only a few months old and it's PLA (eryone). I've kept it on the shelf and it's not been too humid so I wouldn't expect it to be wet - I've tried this with polyterra pla and I get similar results. I don't see bubbles or anything when it's extruding.I'd really appreciate any ideas as I seem to have tried just about everything. Thanks!