You could use less primer and use a hot start polymerase. Initially use a Ta of 50c but consider using touchdown pcr. Check the od260/280 ratio of your dna template is close to 1.8 and that the amount of dna per reaction is 50ng in a 50ul reaction (scale down the dna for smaller pcr reaction volumes).

Consider designing new pcr primers that anneal at 60c using online primer design software to minimise the chance of primer dimer

in addition to what Paul Rutland said I would also recommed to do a gradient PCR to optimize your annealing temperature and to check the integrity of your template DNA on gel (if you haven't done already) because you can have a good 260/280 ration but your template DNA is degraded. I don't know what your annealing time and your primer concentration is but sometimes optimizing the annealing temperature and the primer concentration can also help (especially with primer dimers). If these recommendations and the recommendations from Paul Rutland don' t help I would also consider new primers.

"In addition to what the colleagues have mentioned, based on my practical experience, primers tend to lose their efficiency over time after preparation. Therefore, I recommend preparing fresh primers and testing different annealing temperatures. Moreover, the way the PCR reaction is prepared and the additives used can significantly affect the results."