I’ve seen it mentioned on Facebook several times, by politically connected groups, and also in the Daily Mirror.
Yep it would split the left vote, just as Reform has split the right vote, so if it does come about the new party and Labour might have to work together to keep the right out.
As I see it, unless Labour can substantially improve the financial situation of the majority of people they will be out of power anyway, simply because Starmer is determined to undermine several very good policies by implementing headline grabbing own goal policies. And even if they do substantially improve the lot of the majority, they will probably still lose the next election because of the lack of media support.
Who knows, maybe a new party with genuine left of centre policies would blitz the rest at the next election. So many people hated Corbyn yet so many polls, including Tory voters, showed massive support for several of his ideas. Ideas that liar in chief Starmer said he would follow through on, when campaigning for the party leadership.