Lemon juice works with sunlight, the citric acid accelerates the oxidising process of UV bit it is very drying. I'm guessing the oxalic acid in rhubarb has a similar effect. Raw honey is extremely slow, it's a very weak source of peroxide.

The only quick way to lighten your hair is persulphate bleach or peroxide box dyes. You can limit damage by dying over coconut oil.
2a-2c, medium texture, porous/ colour treated. Three years CG. Past bra strap length heading for waist.

CO-wash: Inecto coconut/ Elvive Volume Collagen
Treatments: Komaza Care Matani, coconut/ sweet almond oils, Hairveda Sitrinillah
Leave in: Fructis Sleek & Shine (old), Gliss Ultimate Volume, various Elvive
Styler: Umberto Giannini jelly, Boots Essentials gel
Flour sack towel, pixie diffuse or air dry.
Experimenting with: benign neglect