Your route isn't mentioned but I would say yes if >3 hours, or if you've never been in the EK A380 F then definitely if >2 hours so you can have a shower and enjoy the seat. for 30k upgrade it's probably a 5-6 hour flight one a J Flex ticket or a 3 hour on a J Saver, very roughly speaking?

Also if you earn 10500 on the outbound you will have 28,000 miles so 2,000 additional mile swill cost you 80$ if you need 30k to upgrade.