Eliminate those layer lines by printing this dome. Once you have all the belts tight, no bent z bar etc and everything adjusted correctly then experiment: Experiment with quality,  layer height,  temperature,  speed,  flow rate etc and just keep changing the values until you get it right. For technical specifications see photo and try 200 degrees for temperature,  40 for speed and 90 for flow rate  on sunlu white pla. Worked for me.