The Ready State Virtual Mobility Coach is like having a virtual Kelly Starrett in your pocket.
In general I’m sure that they are fine. The question is not whether or not they’re okay but are they the answer to your problem? It’s hard to tell. These issues generally have any combination of three issues 1)tissue extensibility, are the tissues long enough ( which the heel drops work on the posterior tissues). 2) joint mechanics are the components properly positioned in the capsule. 3) motor control ( are you moving well?)
The thinking is that the straight leg focuses on the gastrocnemius and the bent knee version is for the soleous. Both are extremely reasonable to stretch and work on unless they happen to have full ROM and you’re impinging in the front of the ankle which could be the issue.
Can you put your feet together and squat all the way down? If so it may not be a flexibility issue you’re dealing with.
As an experiment I’d try to add some distraction work to the ankle before the heel drops. is the pain better same or worse? And does a feet together squat get better same or worse?