I have 5 days to spare in France. Corsica worth it? I've been to Sardinia already so not sure if it's to similar
It has beautiful beaches like Sardinia and it is very rugged like Sardinia. The landscape is generally more lush than Sardinia, which is more arid. Corsica also has much higher mountains. It is also more expensive than Sardinia.
Whether it is worth going or not, depends on your priorities. It is a great destination for a nature type visit, and it has some nice ancient towns like Porto Vecchio and Bonifacio. You will need to fly there, as going by sea takes too long.