Covering greys

[CandysKisses]

I'm 42 and my greys are spreading!
For the past few years I've been doing a home semi permanent hair dye every 2 months but now my greys are fighting the semi dye pretty quickly at around 4 weeks they are showing through.

I have very dark brown hair, do I go for permanent dye? Do I need to have this done at a salon to prevent it killing my hair? It's pretty fine as it is.

What to do? Any advise greatly received!

L'Oréal Excellnce if it works but if you have resistant grey -Majirel.

Is that permanent?

Yes they both are.

I use permanent dye and the roots still come through, especially at temples, in 3-4 weeks.
I find a temporary root cover up powder applied with a little brush ( e.g. Color Wow or similar) works better than the sprays or hair mascara type products. I've tried lots of different things....