Dye for grey hair or not?

[MrsFogi]

So I bought two (semi-perm) hair dyes - now that they have arrived one says that it is for use on grey hair (L'oreal) and not to use on non-grey (Josh Wood) and the other says not to use on grey hair. I had my hair (perm) dyed just before lockdown and the roots are growing out and revealing the horrifying fact that about 80% of my hair is grey.

So I am at a total loss which to use - given that I have a good sprinting of grey roots to cover but also a sprinkling of brown hair and then the lengths of my hair are brown.
Can anyone enlighten me?

Use the one for grey hair but do your roits first for about 10 mins then put colour through the ends for rest of time. This will allow the roots to colour and it will blend the rest in.

Thanks @Eggnoggoanngoanngoann