What kind of management is most effective for hair loss treatments?

Lately, I’ve been so upset because my scalp along my part looks white whenever I look in brightly lit places or elevator mirrors. Even when I tie my hair up, it feels sparse, and I get scared whenever I see handfuls of hair falling out every time I comb it. I’ve been using supposedly good functional ampoules and scalp massagers for months now, but they aren't very effective...

So, I’ve finally decided to bite the bullet and am looking into getting professional hair loss treatments. There seem to be quite a few types of treatments available, such as exosome injections, stem cells, and mesotherapy, but which treatment would be most effective for improving density along the parting line on my crown? I don't think a one-time treatment will be enough, so I’ll likely need to sign up for a package; typically, how many months do I need to go consistently for fine baby hairs to start growing in?