My hair just frizz two weeks post colour - what can help?

[Thisisnottheone]

Currently I pay a lot of money every 5-6 weeks to try to keep the greys under control. Foil blondish highlights, root touch and a toner. The toner lasts perhaps a week tops. My hairdresser has been great, we don’t use many foils now to try to not bleach it very much.

My hair is a dry frizzy mess by week 4 and the roots are back and look bad by week 6.

I use some wella oil pre blow dry, a heat protector spray and blow dry with a GHD round brush, then straighten it with GHDs.

I have a Dyson, a shark and a GHD hair dryer.

Any advice on shampoo, conditioner, treatments? Nothing seems to work. The grey hair underneath is so different to the nice shiny hair I once had. I would love some good advice. Unfortunately I think growing out my grey would just leave me with horrendous frizz.

The blow drying is fluffing it up.

Rub in a small amount of light serum after washing, dry to 80%, then straighten lightly to smooth the hair shaft. After than you can add curl if you want but the hair itself will be much smoother and more manageable.
I have naturally curly hair (former redhead) that tends towards frizz and this works for me.