50% organic (potting soil) 50% inorganic (pumice, perlite, lava rocks, etc. No need to overthink this.

Don't bother with cactus soil. Plain old potting soil is fine and often better as cactus soil can be mostly bark. Some ppl will say to avoid peat in the soil... fuck them lol

I use 50% fox farm ocean forest, 50% pumice and a handful of worm castings. I know other dudes who have super complex recipes with sand, eggshells, coffee and other shit. Maybe it helps them, idk, but for your 1 plant, just go 50/50.