AFAIK, L1 are hardware backed using Trusted Execution Environment like ARM TrustZone. Unless you can find an exploit to exfil the key from the chip, you have no luck. It was done before and published, but I believe it is patched already. Anyone holding such exploit would keep close to their chest to avoid it beimg patched.
Maybe. I’m not in the loop but I believe you would need to gain some solid trust from the core team to get that access. It won’t be a knowledge just flows in the scene up for any newly join members to grab.