I am so confused as to which way to go. We use a conditional mail merge using multiple documents in donor ack letters in RE. Power Automate seems really complicated where as ReceipterPro v2 seems easier after watching their demo. Thoughts on what you plan to do if you are using conditional mail merges.
Example of what we are currently doing - If someone gives a one time gift they receive letter A, If someone pays off their pledge they would get letter B, and if someone gives a gift to a specific ministry (we are a church) they get the letter that corresponds to that ministry. We also do honor/memorial acknowledgment letters.
Thanks