Hopefully he takes votes from Biden costing him the election. The hard truth though is that Trump is a losing candidate and we will be doomed to four more years of who ever controls brain dead corrupt Biden.
As things stand today I would expect Trump to beat Biden with or without a significant 3rd-party presence. Creepy Uncle Joe abandoned all his campaign promises, seems determined to start WW3, and is obviously in worse cognitive shape now than in 2020 (which was already bad shape). Even democrat voters don't want him to run again and are disgusted with the party for ignoring not only their left-leaning voters (that's just standard procedure these days) but everyone else too this time around.
The "squad" and other so-called progressive democrats can't save Joe this time because voters have seen who they really are and had enough of their shit too.
As long as Biden's republican opponent (whoever that may be) is opposed to the proxy war in Ukraine poor ol' Joe is likely toast. That issue puts Biden to the *right* of candidates like Trump who at least make anti-war mouth noises. It will be exceedingly difficult for democrats to sell Biden as the "safer" candidate with the massive quantity of undeniable evidence that such assertions are, to coin a phrase, a bunch of malarkey.
Speaking only for myself although I'm certain I'm not alone my vote can't be "taken away" from Biden by a 3rd party candidate because Biden never had and never will have it in the first place.