$path =~ m/((?<=[=_:])\d+)/g

##</code><code>##

$ perl -E '
    my $path = q{/.snapshots123/yabsm/root/hourly/day=2021_03_04,time=21:20};
    say for $path =~ m/((?<=[=_:])\d+)/g;
'
2021
03
04
21
20

##</code><code>##

$ perl -E '
    my $path = q{/.snapshots_23/yabsm/root/hourly/day=2021_03_04,time=21:20};
    say for $path =~ m/((?<=[=_:])\d+)/g;
'
23
2021
03
04
21
20