If both heater core hoses are hot, then there is heat into the core/cabin. It isn't making it into the passenger compartment which is likely a faulty blend air door as you mentioned.
To get you started, here is a link that explains in general how one is replaced. You can use this as a guide.
If you look at the attachments below, they are the directions specific to your vehicle for the replacement.
Let me know if this helps or if you have other questions.
See pics below.
Images (Click to enlarge)
Saturday, January 29th, 2022 AT 3:26 PM