In my opinion, neither platform wins here.
Squarespace does have an Events Calendar function built in, but even with all the cool features it does have (like event-share buttons & a map for the event location), the date features aren't very robust. For example, if you have the same event, at the same time, every Friday through Sunday, you'd have to create 1 event listing for each day over that weekend (x3), for every weekend you host it, –because Squarespace doesn't have the capability yet for 1 event to cover a multi-day space for only a specific time frame. You could label the event as taking place Friday through Sunday, but you'd have to choose 1 start & 1 end date, which only covers the event time for 1 of the 3 days. (It'd be listed as Fri 12p - Sun 3p, instead of Fri 12-3p, Sat 12-3p, Sun 12-3p)
There are lots of great plugins for calendars, like Elfsight, which use code block or embed block and they're super simple to use.
Of course you can also just design your own, but it may look a little clunky, depending on your design capabilities.