Since the official announcement of HubSpot about the sunset API Key integration method on June 1st 2022.
We have transferred the HubSpot integration method by Access Token. Application for Piotnet Forms 2.0.10 and over.
Different descriptions in summary:
Create Private Apps > Set Scopes > Get the Token > Complete Piotnet Settings.
For more details, please refer to the updated document.
All the best