This is a streamlined version of my previous question (LuaLaTeX 64 bit does not finish compilation).
My setup: Windows 10 (or 11), current TeXStudio, TeXLive 2021.
I attempt to use the 64bit binaries for my compilation. I was able to do that before, around TeXLive 2019, I suppose. As far as I remember, it involved only:
Downloading the files from https://ctan.org/tex-archive/systems/win32/w32tex/TLW64/
Creating a win64 folder in C:\texlive\YEAR\bin
Adding this C:\texlive\2021\bin\win64 to PATH before the 32bit version.
I remeber being able to handle my problems with files not compiling otherwise this way.
Now when I try to compile in TeXStudio (putting, for instance, "C:\texlive\2021\bin\win64\lualatex.exe" -synctex=1 -interaction=nonstopmode %.tex as the command for LuaLaTeX in TeXStudio settings), the files do not compile in LuaLaTeX (the log is stuck in an infinite cycle), pdfLaTeX does not even start, but 64bit XeLaTeX runs without a hitch.
As far as I understand, the 64bit binaries were not even supposed to run out of the box without some additional preparations. Hence, my question: as a user, what procedures should I implement after installing all of these files in order to make LuaLaTeX and pdfLaTeX in their 64bit versions compile without problems in TeXStudio?
Bonus question: how can I keep them side by side? Is there a way to setup them in a way that I could compile with whichever version I want just by tweaking '32' and '64' in the path string for the file I am compiling with?
Mostly interested in LuaLaTeX, as I use Lua-specific packages heavily and sometimes cannot handle the result with the 32bit version.