I recently ran into a similar scenario. We added a space to our store that can function as a classroom or maker space. For a 1 on 1 class Square appointments worked great. For the maker space rental we are able to allow up to 4 people to use the space at one time and Square didn't have the ability to allow for this.
I tried Skedda conference room booking software and while it offers multiple bookings at once it doesn't allow for the options of equipment rental that we needed, and won't pull info from another calendar. So if we make a class appointment in Square it wouldn't block the time out.
Then I found Koalenda. It allows for multiple bookings at once and after a quick conversation with the owner (on a Sunday even) he spent a day to implement a multiple choice option for questions while booking. Now we have an online booking calendar that allows up to 4 customers (per day) to choose the day they want to book the room and gives them a list of equipment (with check boxes) that they may want to rent while they are there. It does not offer the multiple price charges, so you would still need to invoice your customer separately, but it does allow for a single charge if you needed a deposit for the appointment. It is a nice clean customer interface that can be embedded into your website allowing them to book their own time slots, and options. It communicates both ways with Google calendar so a Square appointment will still block time out as will vacation or day off events added to the calendar.
Not as nice as a full Square solution, but when I was searching around and I saw that this was yet another topic that has been requested for several years now I figured I better find another solution rather than waiting on a Square update. Hopefully this helps some of you as well.
