Still waiting for nip-67. That should fix main key security concerns.

However using #[4] extension is perfectly safe as your private keys don’t touch the clients. Extension simply signs all the requests you authorise it to sign.

I’d go with Alby to avoid dealing with a bunch of keys later. Plus if you end up enjoying habla (which I believe you will 😉) you won’t have to go through the trouble of deciding what to do with your posted materials (repost with your original key / leave it etc).

Moreover using the same key makes it easy for habla readers find you on other Nostr platforms.

Hope I helped a bit.