Take a flight or purchasing something with a co-branded card seem the only things. I am not sure if donations to charity which give XP count as ok activity. You could try that for a modest amount (2000 miles = 1 XP) and see if that changes the expiration date, but I have little hope since the T&C suggest only flying activity helps.

https://awardwallet.com/blog/air-fra...-miles-expire/
Flying Blue miles expiration date?
https://www.flyingblue.us/en/news/extend-miles