Apologies, the “file” command is probably not available in Lakka, that’s why it failed. It would have shown you whether the executables are 32 or 64 bit. That would have helped to determine if the error is related to this one:
executable - Getting “Not found” message when running a 32-bit binary on a 64-bit system - Unix & Linux Stack Exchange
It might be possible that the vcgencmd you have is 32-bit and your Lakka installation is 64 bit. In that case, I’d try to obtain a 64-bit version of these tools, if available, and then copy them to your SD card’s storage partition and run them to test if that works.
But after a bit of googling, it seems that vcgencmd is part of the official Raspberry Pi firmware package, which seems to be only available in 32 bit. In that case, my suggestion would be to test the 32-bit version of Lakka for the RPI4: Lakka - Nightly