I issued some changeProxyAdmin calls that updated the proxy admin to the wrong address, now when I try and fix it with a new call it errors with a generic message. How can I fix this? Do I need to deploy a new proxyAdmin? If so how do I point the proxy at the new proxy admin?
The proxy admin of a transparent proxy is the only address that is allowed to call the proxy's administrative functions, including its changeAdmin and upgradeTo functions.
A proxy admin could be an EOA or another contract (such as ProxyAdmin) that is able to call the proxy's changeAdmin and upgradeTo functions.
In this transaction, since you accidentally set the proxy admin of a transparent proxy to the transparent proxy address itself, this is not recoverable. The transparent proxy does not have the code to invoke its own changeAdmin or upgradeTo functions. Therefore this proxy became non-upgradeable. The only way to fix this is to deploy a new proxy with the correct proxy admin address.
Any other proxies using that proxy admin would not be affected though, since that proxy admin is still the admin of the other proxies.