Hi,
It looks like modifying the esx.conf file has caused ESXi to fail at boot, and now you're running into issues with local.tgz, specifically a SHA1 certificate validation error. This happens because ESXi uses local.tgz to store its configuration, and if something gets corrupted or altered in an unexpected way, the system refuses to load it.
Since you've already tried mounting the disk using a USB (Ubuntu) but couldn't extract local.tgz, there are a couple of ways you could go about fixing this. If you still have shell access, one option is to manually mount the boot volume, extract local.tgz, fix esx.conf, and then repack everything. However, if the system doesn't let you do that or if you're stuck at boot, reinstalling ESXi while keeping your VMs might be the easier route.
The good news is that reinstalling ESXi doesn’t necessarily mean losing your VMs, as long as you don’t format the datastore during the installation process. Once ESXi is back up and running, you can manually re-register your VMs by locating their .vmx
files and adding them back to the inventory.