Honest first point: you can't reliably judge thinning from three photos taken years apart in different light, lengths and cameras. Shade is the biggest trap. "Temples not as dark" is exactly what lighting fakes, and the temporal points naturally carry fine, pale framing hairs that catch light differently shot to shot. Some of what you're seeing is likely the photos, not your scalp.
On the dutasteride regret, I'd push back gently. Dutasteride is a stronger DHT blocker than finasteride, not weaker, so switching up wouldn't cause more loss. Intensifying treatment can trigger a temporary shed that looks worse for a few months, but two years in that's long behind you. dutasteride should be protecting you more than finasteride did, not less.
The one real caveat is location. The temporal points are the most androgen-sensitive and least responsive area to any medication. Meds hold the mid-scalp, crown and central hairline far better than the corners, so slight softening right at the temples while everything else holds is common, and not a sign your regimen is failing.
Across five years, a hairline that's broadly held is a good Androgenetic Alopecia result, not a failure. But stop reading it from mismatched photos. Get trichoscopy to measure miniaturization properly, or at least take standardized shots, same light, length and angle, every few months. That's the only thing that'll actually answer your question.
I doubt that it's just a shed, can you even shed 2 years into dutasteride and min?