> And indeed, Proc::Background is pretty much exactly what I was hoping for. Thanks a lot!

Well ... Proc::Background relies on Win32::Process

package Proc::Background::Win32;
$Proc::Background::Win32::VERSION = '1.30';
# ABSTRACT: Windows-specific implementation of process create/wait/kil
+l

...

use Win32::Process qw( NORMAL_PRIORITY_CLASS INFINITE );   # <---

...
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update

and that's how it's avoided as dependency on Linux

https://metacpan.org/release/NERDVANA/Proc-Background-1.30/source/dist.ini

[OSPrereqs / MSWin32]
Win32::Process = 0.04
Win32::ShellQuote = 0.003001
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