Service add-ons available during appointment booking by client

[Spiro_Spero_Spa]

I'm an esthetician and I need my clients to be able to schedule add-on services to their facial appointment (ie waxing) at the time they are booking. Being able to schedule additional services as add-ons allows me to allot appropriate time as well as anticipate revenue since add-ons generate additional revenue. I've tried setting up modifiers - that didn't work. Then I variations on every.single.service (I have 10 add-on customizations for each service) but clients can only choose one variation per service - what if they want a brow wax AND a lip wax - they need to be able to choose multiple variations under the parent appointment. I'm really frustrated. Would love to know if anyone has found a way for service providers to workaround this massive issue!!

Previous posts are from 2022 and earlier - when will Square catch up? @admin