From Apple Support:
You can add up to 32 items in Find My. In addition to AirTag and the third-party Find My network accessories in the Items tab, AirPods Max count as one item, AirPods and AirPods Pro (1st generation) count as two items, and AirPods Pro (2nd generation) count as three items.
Good to know. This will put a tamper in my current obsession with getting Find My devices every time there’s a sale.