It's not just the base colour you need to even out it's also the porosity or you risk still having uneven colour. Also be aware of cuticle staining, and of the possibility of silicones have melted onto/ into your hair if you have used high heat - honestly nothing will get either of those out save a pair of scissors.

Use a colour remover (no peroxide) not a stripper (contains peroxide), these can generally be used three times. The technique is quite specific you do need to keep your head warm during processing and agitating the hair loads during the lengthy rinse.

When you redye use a non damaging high pigment semi permanent instead of a demi, with red actually this lasts just as long if not longer than permanent and can be touched up as often as you like with no damage. I leave mine on for three hours, some do overnight, I also CO-wash in cool water which is much gentler than shampooing.

Do strand tests with shed plughole hair rather than experimenting one on your whole head.
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/ fractionated coconut oils, Hairveda Sitrinillah
Leave in: Fructis Sleek & Shine (old), Gliss Ultimate Volume, various Elvive
Styler: Umberto Giannini jelly, Au Naturale styling gelee
Flour sack towel, pixie diffuse or air dry.
Experimenting with: benign neglect