I am also getting achilles issues now (due to more supination and inward rotation of the affected leg). I am almost positive it’s due to footstrike like you said. Historically I always had noticable bilateral external rotation of both legs. I am also pretty sure that hip/sacrum malalignment is a factor and my therapist could greatly improve the situation but it’s a matter of ‘do I want to pay $100 and drive 1hr each way’ when I am not competing much at all anymore? The main idea here is that 90% of therapists don’t seriously look at bony hip alignment with this injury when it is most certainly a factor in a good % of cases.