Picking a WAF configuration for a voting application

We have an Amplify hosted application that effectively has a voting component - where the URL has an identifier as part of it to cast a vote - so, for "Yes" the URL goes to https://domain.com/vote/?answer=YES and no goes to https://domain.com/vote/?answer=NO There are rules around voting, so we save a client-side cookie as to whether you have already voted. So, the URL hits our server, it responds with a redirect and a cookie to log the fact you voted on the client machine. So, if you go to vote again, it sees the cookie and either doesn't allow your vote or changes the prior vote. We clearly don't want bots voting, so it looks like putting WAF in front of the URl would help. There appear to be an infinite number of WAF configurations. Does anyone have a configuration suggestion that would allow us to protect the voting URL from fraudulent use?