[2023] I don't understand the workstation leveling skill

Wiki is outdated and not up to date with A21. In A21, you no longer unlock crafting recipes with skill points; Instead, it has all crafting skills behind reading magazines you loot or buy; The one you're looking for specifically is Forging Ahead iirc, which you need to read 30 of to unlock the mixer, and you only have 29... so get one more and you're done.