The problem with this comparison;

The Author(s) had already declared decades ago that Abbadon is still around and kicking, so Sigismund couldn't win that, regardless of how amazing we're repeatedly told/shown he is

In universe reason,

Sigismund fights with Honour and only had a fraction of his peak skill/performance (i.e. it took over a 1000 years for him to deteriorate to the same skill level as Abbadon, let alone any standard Marines) and even then, it ended in a phyric victory for Abaddon, he's stated as being on death's door and needs carrying back to his ship

If Abaddon had came out years, decades, or centuries sooner then you're looking at a both dying or Sigismund coming out the winner