As expected a ST¹ solution was posted. As usual, no GRT² variant was. Since I think that if the list you're sorting is large enough to benefit from an ST, it'll benefit more from a GRT, here's the GRT variant:

my @seq = qw[
      1035-2341
      1047-835
      1035-2347
      874-3971
      1035-65
      874-70
      1035-46
];


say for map {join "-", unpack "nn", $_}
        sort
        map {pack "nn", split "-"} @seq;
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Of course, for a 7 element list, neither ST nor GRT gains much benefits.

¹Schwartzian Transform
²Guttman Rosler Transform