Quote from Top Hair Loss Treatments on June 2, 2020, 8:45 amI hate to be the bearer of bad news but if you are a male over 18 years old and losing your hair it will almost certainly be male pattern baldness/androgenetic alopecia (AGA).
When you say you are experiencing diffuse thinning across your entire scalp, do you mean the back and sides too? If so, then maybe it could indeed be telogen effluvium. However, if your hair loss is concentrated on the top of your scalp (particularly the temples and crown), then it is almost certainly AGA.
It sucks, I know, but the interventions you mention (particularly finasteride, as long as you don't get/can tolerate side effects) really do work. I would advise you to speak to a doctor and potentially get on finasteride as soon as possible. This is because it is much harder to regrow hair lost due to AGA than maintain it.
Hope this helps! :)