Channel/affiliate partners send users to your branded site or app, and users sign up to YOUR service and become YOUR customers. You have the right to up-sell and cross-sell to them. You get to establish cross-partner network effects. They don't typically pay you. You might even pay THEM commission for leads.

B2B2C products are typically when your product is white-labeled or embedded into a 3rd party site or app. Users sign up to the OTHER service and do NOT become your customers. You do NOT have the right to up-sell or cross-sell to them. The 3rd party site or app typically PAY you as your CUSTOMERS.

Don’t confuse the two.

Don’t accidentally stumble into B2B or B2B2C when you really want to do B2C and/or affiliate.