Time to update the first post with how 11.3 was hacked. My attempt at a writeup follows.
After 11.4 showed up, and patched it, UDSploit was released. This is an arm11 kernel exploit that functions on 11.3. The developer held it back because it enabled piracy on current firmware, and he wanted to support homebrew only. Additionally, safehax (the arm9 exploit from 11.2) was updated to function properly on 11.3 (nintendo didn't quite fix it properly, as there was a way to bypass the new check). So we use Soundhax to get arm11 userland, so we can run UDSploit to gain arm11 kernel, so we can run updated Safehax to get arm9 kernel. With arm9 exploited, we can once again run a CTRTransfer utility to downgrade to 2.1 so we can fetch the OTP and install a9lh.
With 11.4, Soundhax and UDSploit are both patched. People believe Safehax to be patched as well, properly this time. Doodlebomb works to break into arm11 userland, but without a working arm11 exploit, we are once again stuck there, as we were on 11.3.