Signal 11 is a SIGSEGV (Seg Fault; aka the code attempted to access memory outside its assigned range, or it tried to write to a readonly segment of memory, or it tried to execute code in a segment of memory not marked executable).
Launchd DOES NOT seg fault. It it the first process started under macOS (PID 1) during boot.
I would suspect either a hardware issue (bad RAM), failing motherboard, failing harddisk (or SSD), or that the launchd executable became corrupt.
Since you replaced you hard disk, I would suspect that either when you copied your operating system over to the replacement disk, you got corrupted data, or that maybe your SATA cable is broken (from unplugging, plugging in disks), or you just have a broken replacement.
You could start by re-installing the operating system (make a backup (or 2) before doing an operating install).