This snap does not meet the requirements for classic confinement and so this is not suitable in this case.
However, as I said above, I don’t think you should even need personal-files if the code can respect $HOME, however if this is not the case then personal-files can be used for access to ~/.local/share/bconf if this is strictly necessary. Also a number of existing interfaces do provide some access to some of the paths under /sys/devices/virtual/dmi/id - can you please be more specific as to which files you require access to from this path? Finally, system-files can be used to grant this access as well.
Please can you respond to these questions and we can try and help.