I’d suggest you ask your audience. There is a regular event I run where people were arriving later and later each time, purely because they know we are friendly and laid back. But it was getting too much and so I contacted everyone explaining ‘we’ve noticed a lot of people struggle to make it for x time, would you prefer we start at y time?’ The replies were overwhelmingly that actually they would rather start on time and so they made the effort from then on. It helps to know you are doing it for your audience not your schedule iyswim.
For the early ones, we give them a bright and cheery welcome and explain doors open at x and if they are at a loose end “whilst we are getting everything set up ready and safe for you here” there is a lovely cafe down the road/nice park/free museum/whatever or a couple of seats in the foyer. Of course once the first early person has gone to the suggested place, other early people are happy to follow!