Thanks a lot for your kind help, @Mauricio_Garnier-Villarre!
I see that the code works, the computational time is quite intensive, though.
There are two current issues. First, when I tried to inspect the convergence, the fitted Stan object does not work with the error message saying that stanfit Error in mcmc.list(x) : Arguments must be mcmc objects. I think I can solve this issue by referring to other Stan issues. Second, the Stan session is oftentimes aborted. This one might have something to do with local RAM capabilities or volumes of the Stan fit objects.
Once I clear these issues, I will share some information about convergence with the current factor model identification.
Thanks a lot!
Cheers,
Ihnwhi