runDisney tracks the races that you run. If you run the inaugural race for a given theme (like Star Wars) and then run every year after in the same themed race weekend, you are recognized as "legacy" at the 5, 10, 15, etc year mark with a different lanyard for your medal (and sometimes extra swag if it is 25 years as a runner of every marathon at WDW since they started...) This is the fifth year (was supposed to be last year before race was canceled due to pandemic) of Star Wars for several things: Kessel Run Challenge and Half Marathon so hopefully those that did all five years will get some sort of recognition.
runDisney stated that they will be changing the theme of Star Wars weekend for 2022 to something else (
https://www.rundisney.com/advisory/) so any legacy would be reset - i.e., you would sign up the new theme next year and every year after to hit the new legacy milestones.
So bottom line, sign up for as many medals as you'd like and no need to worry about legacy status for Star Wars for this virtual race.