As of November 1, 2020, U.S. citizens from all 50 U.S. States and Washington, D.C. will be allowed to enter Costa Rica with the proper insurance and completed Health Pass. US Embassy Information
So let's look at option for Delta flyers in Southern California in particular the San Diego area as it is easy to access Tijuana Airport from San Diego via the Cross Border Xpress (CBX) which is an airport terminal located on the United States side of the border making it easy to fly out of Tijuana Airport. The CBX is open and has improved safety measures in these troubled times.
TIJ-SJO would earn 7845 MQMs 2092 MQDs 5.41 MQD Ratio
Delta Diamond members would obtain 23012 RDMs, Platinum 18828 RDMs, Gold 16736 RDMs, Silver 14644 RDMs, Base 10460 RDMs