M27: My hair looks dull, thin, and weak — should I go for a hair spa or salon treatment

Over the last couple of years, I’ve noticed my hair becoming dull, weak, and kind of lifeless. It used to have a healthy look earlier, but now it feels rough and thin. I’ve also some premature grey strands and mild hair reduction.

I’ve been thinking about going for a hair spa or salon treatment, but not sure which ones actually help and which are just marketing. Do salon spas (like keratin, protein, or scalp treatments) really make a long-term difference, or is it just temporary shine?

Any recommendations?