This is the issue: How to fix under extrusion after travel
It can be caused by a few things. First and easiest is to do a cold pull and use a nozzle cleaning needle to clear out any possible clogs. If that doesn’t help then it is likely the bowden gap. All creality and similar machines will have that issue after some number of print hours - the bowden tube backs away from the nozzle making it difficult for your printer to reach proper pressure. To fix it you need to properly reseat the bowden tube. See here: How to fix under-extrusion caused by bowden gap