I am completely flabbergasted by this DOSbox idea!
It is apparently possible to make a super, super crippled version of Perl under DOS, PerlDos. However, this will not "do anything useful". The DOSbox has all the memory limitations of DOS.

Under the Mac O/S, it is possible to create a virtual Win X machine. I have friends who do that. This requires a "honking machine".

You say, My current version is FC2, running on 64-bit Ubuntu Linux.. For the DIY crowd, I would think that a Raspberry Pi 3 is one idea. Port the code so that it runs on the Pi's Debian O/S and on your Ubuntu Linux.
DOS emulation is a "dead duck".

I have one DOS program that I want to run on my current Win 10 machine. This is a huge mess to deal with because of emulation of the sound card device drivers. When I had a Win XP machine, I would just re-boot from a floppy disk and run it. I can't do that now and need DOSbox.

Anyway, running Perl under DOS is an insane idea.