is there some way to delegate access to a farcaster account through UI? for example to give access to the defillama account to other people

Low tech solution: when you give access to another app to post, it does it with a new signer. So worst case you can use different clients :D

and then you can revoke the signer later?

can the other signer revoke your signer as well tho? imagine they get hacked and hacker kicks you out

I've only tried it via privy, there are some interesting caveats, e.g. when you revoke, the messages posted by that signer get deleted. I'm pretty sure those signers cannot revoke others though.

I've only tried it via privy, there are some interesting caveats, e.g. when you revoke, the messages posted by that signer get deleted. I'm pretty sure those signers cannot revoke others though. https://docs.privy.io/guide/react/recipes/misc/farcaster-writes#faq