In the UK, Labour's hard left turn helped cement a long run of tory government; only Starmer's forceful rejection of his party's far left flank brought Labour back.
Maybe you're over-reading a single datapoint and neither France nor the UK are good proxies for "all political contexts everywhere"?
The lesson of the French elections really seems to be “only a united coalition can beat back the forces of tyranny” and not so much about whether leftism or centrism are inherently superior political philosophies.
In Australia we do our ranked choice voting in one Saturday rather than two Sundays.
There's a full flow of preferences but that's not important right now.