I have dark brown hair on my head, however my sideburns and beard are brighter (beard is a complete mix of brown, blond, some grey, but no red tones!), while my eyebrows have a cold brown, almost black...

I used to order hair system (long hairstyle) in a 50:50 colour mix of #2 and #3. However the hair quality hasn't been good there, lately. When I changed to a different seller who fulfilled all my custom specifications, the quality has been very good, but I could only choose between #2 and #3, no mix possible. And as for #3 I found out, that it is actually a nice colour, but it is too "reddish" for me to match the rest. When standing under light, it has a red shine which my actual hair doesn't have.

However, if I took colour #2 only, there might be less red tones in it, but then I'm afraid that it could look odd in combination with my rather bright beard.

Would you say too dark hair is more likely to look suspicious, or is too bright/warm/reddish tone rather suspicious?
And which one would be easier to fix? I'm not experienced with dying hair to a different colour, but I heard it would always do a bit (additional) harm to the hair structure.