Disable the inbuilt poll command with command overwrites and after that add the custom commands.
When adding -single anywhere in the trigger you can force people to only choose one reaction and whenever a user reacts on 2 reactions his old reaction will be removed.
Due to the reaction part of the code having a huge anti spam part to prevent people from spam clicking the reactions and crashing the custom command yagpdb, it will wait before removing multiple emojis the user reacted to.