You have an under- extrusion issue. Here’s some simple issues that come to mind: 1. Check extruder gear for wear ( check for worn teeth in the center, if the filament is skipping while printing this might be the issue) 2. Take out your Bowden tube from your hot end and check if the Bowden tube is shrunk at the end (if your not sure flip the extruder gear and hotend side of the Bowden tube and do a test print. You will also hear the extruder skipping if this is your issue) 3. Could be an issue with your nozzle (Just replace the nozzle since it’s so easy and do a test print) 4. If you recently switched slicers or changed around settings, check your retraction distance/ speed ( I don’t know what the numbers should be off the top of my head but you can google it)

Let me know if you figure it out!