OK, I can only say - don't do what I did, which was to impulsivley buy a box of permanent brown goo that looked great in the picture. I did not look great on me, it looked horrendously dull and fake, like a bad wig, and I spent the next three weeks wearing hats and washing it twice a day until it had faded.
Go to a good hairdresser who specialises in colour - or better, go to a couple - and ask their advice.
Now I have three shades of brown & blond threaded into my own colour every three months or so, & I'm very happy with it. When it's growing out it's not too obvious.
One vote for DIY colouring - purely for financial reasons! But then I have naturally dark brown hair so it's an easy colour to replicate on the cheap. The thing about highlights is it won't cover all the grey, I'm guessing.
I started out with an 'all over' brown, then they pulled out strands through a cap & made them different tones, very fine so it all blends in.
But then another hairdresser suggested it would look OK without the 'all over' colour, so she uses three toning colours & again, thin strands. You can still see some grey if you look hard, but it all blends in & is quicker & cheaper & looks natural, and doesn't show re-growth unless I leave it for about 4 months.
I'm not suggesting the OP gets into an £80 per month colouring habit, but just for starters to go to a hairdresser with lots of colour experience, get some advice, & try it out.
It would be no good for you obv. I now have an all over glossy brown with vivid red sections. I've tried the 'sunkissed' look but too many hairdressers gave me tiger stripes which I hated. (I don't often go to SIL because she is mostly far too busy and our free times don't tend to match)
I caught a glimpse of ?This Morning this week and thought the woman on there had beautifully-coloured hair.