FCC is only required if it contains Wi-Fi or Bluetooth electronics
There are different levels of FCC testing/certification. Testing is required for anything that operates above some frequency (9 kHz), which includes virtually any digital circuit or switch-mode power supply. Certification, the more stringent form, is required for intentional radiators, things that broadcast RF as part of their function, including Wi-fi and Bluetooth. See for ex https://blog.clevercompliance.io/electrical-product-compliance/do-i-need-fcc-certification/
