How to make beans more neutral tasting?
In most beans, heat around ~104°C to ~110°C will destroy many of the flavour compounds (a slightly different but precise heat is used for different bean varieties)

Commercially beans are steamed in that temperature range to neutralise them before being processed (e.g. making bean derivatives, or milks)

For domestic processing you could try steaming them in a home pressure cooker to achieve the same effect

Also, many beans are soaked at ~60°C for some hours prior to processing to reduce the "fart" sugars