Embedded Systems Engineer - Raspberry Pi + Square Payment = Controlled Automated Massage Chair

I am building a custom luxury home spa using a massage chair that is for home use, and need an experienced embedded systems engineer. The goal is to allow a residential at home massage chair to require payment before each massage session using a Square payment terminal. The goal is to create a massage chair that will not work without payment to a personal savings account. Desired workflow: • User taps a credit card, debit card, Apple Pay, or Google Pay. • Square approves payment. • Raspberry Pi enables one massage session. • The chair runs its normal built-in 10-20-30-minute program. • When the massage ends, the chair returns to its home position. • Another payment is required before another session. Important: I do NOT want to abruptly remove power from the chair. The solution should safely interface with the chair’s controls while preserving its normal operating and shutdown sequence. The engineer should recommend the best massage chair model for integration if needed. I am open to recommendations if there is a better approach than Raspberry Pi. I would like to use Square if practical, but I am open to Stripe or another payment platform if it results in a simpler, more reliable, or lower-cost solution. This system is intended for private residential use and is not intended for public operation. Experience with Raspberry Pi, embedded systems, Python, payment APIs, kiosks, vending machines, arcade machines, access control, or automation projects is highly preferred.