If you've got a new device and aren't sure how to set up your Sweatcoin account on the new phone, just take a look at the steps below for your specific case:
iOS > Android
1) Go to Profile settings on Sweatcoin app on the old iOS device
2) Set a new email and confirm it directly in Sweatcoin Profile settings that you'd use on your new Android device (123213@privaterelay.appleid.com => johndoe@gmail.com)
3) When signing in on your new Android device, please use your new email (jondoe@gmail.com)
Android > iOS
1) Go to Profile settings on Sweatcoin app on the old Android device
2) Set a new email and confirm it directly in Sweatcoin Profile settings. This email must be linked to your AppleID
3) When signing in on your new iOS device, use "Sign in with Apple ID" button and allow email sharing (otherwise it won't work)