Bleach bath after Affinage bRED and Colour B4

Hi everyone! This is going to be long so apologies in advance, I'm not good at being concise!

Several years ago I started using Affinage bRED in Red with 30 vol to dye my hair. I have naturally brunette hair and I'd used dark red box dyes before, so Affinage was my first experience into properly lifting my hair (more than a box dye does anyway). I used it all over the first few times with a slightly lower developer on the lengths and it worked really well, but then I cottoned on to the fact I didn't need to keep processing the lengths. I also didn't know at this point that colour doesn't lift colour. I then changed to maintaining it by using the Affinage on the virgin roots only and Crazy Colour Fire on the lengths to refresh the colour.

I've been doing this for years now, and have noticed my hair isn't as bright as it used to be. I started to wonder if maybe the layers of red were somehow stopping it being as bright, so I used Colour B4 a few weeks ago. It worked surprisingly well considering how many years of dye were on my hair - it went to a light auburny/strawberry blondey colour which I figured would be a good and light enough base to put Crazy Colour Fire over. I dyed it with Fire again and my hair is maybe a tiny bit brighter, but still nowhere near as bright as it used to be years ago.

I don't know why my hair isn't as bright as it used to be, and even though colour doesn't lift colour I was wondering if using Affinage bRED on the lengths was still lifting it a bit? I've researched hi lift dye and from what I've read it doesn't work on lifting already lifted hair, but it definitely isn't as bright as it was.

Finally, I am wondering whether to do a bleach bath to lighten everything just a little more to hopefully get the bright result I want. Does this sound like it could work? I've been reading and reading on here so I know to use coconut oil and do the roots last. I'm very careful with my hair too - washing in cool water once a week, sulphate free haircare, no heat etc so it's hopefully not too damaged (hairdressers always say it's in good condition). I've never played with bleach before apart from Affinage so I don't want to get it wrong!

Thanks so much for reading my rambling and any advice you have. I have attached photos of my hair to show how it's changed - first is how bright it used to be, second is after Colour B4, third is literally 5 seconds ago. It does look a bit brighter in sunlight but it's still a far cry from the bright photo as I hope you can see!