Ankle supports have their uses but are no good long term. Wear one whenever you do any activity that may cause increased stress or risk of re-injury eg running, football etc
At the same time you should be doing strengthening exercises regularly (daily) through range of motion with a theraband (look on YouTube) and also some proprioception (balance/muscle reaction) exercises eg. Stand on one leg, close eyes or use a wobble/rocker board.
It will take time. Biking will help increase strength and flexibility as theres not too much inversion/eversion of the ankle which is what usually causes re-injury. Unless you get trapped in your cleats and fall on it like I did last week… 🙂