I sincerely doubt that it will bring Trump down - that man is the cockroach of politics, nothing seems to harm him. However it is very likely that the whole sordid affair will severely damage the Republicans - the extreme MAGA crowd that buy into the conspiracy nonsense will desert them and we may find other smaller factions will start to break off.
Musk will be able to play into this: he doesn't need to pay for a whole new party just buy himself 4 or 5 congressman/senators so that the balance of power in votes sits with them.
Best case scenario - dur to infighting the Republican vote collapses at the Midterms, the Dems take back the House and/or Senate and Trump is a lame duck for his final two years.
Even if the Republicans manage to hold it together for the Midterms, it is highly unlikely that the next nominee, be it Vance, Trump Jr or whoever, will be able to hold things together in the same way DJT has and the whole house of cards is likely to collapse.