From what I've seen, most of Diocletians palace is free, outside of Jupiters Temple, and the Cathedral of St. Dominus. I have 2 questions:
1) Do you have to buy tickets ahead of time due to covid? And is there a line? E.G. The vatican it is always recommended to purchase online to skip the lines, and now post-covid you can only buy tickets online.
2) Where can you purchase said tickets online? I have tried searching, but found nothing but tours. Can you only buy these tickets in person at the time of arrival (i.e. can't buy tickets before hand online)?