Chance of Trump win 2024 is near zero, you just need to look at Mid-Term 2022, and then the debacle of House Speaker vote, Trump brand is gone and has been since 2020. Everybody know it but Trump.
On the other hand, US already pledged support post 2024, and if they are going to pass the other bill that secure that 45 bil lodged last December passed both house (Definitely Senate, highly likely Congress) then US support to Ukraine would remain at least until 2026. With or Without Biden in power.
This is a bit too optimistic IMO. As we saw with the Speaker election in the House, there is going to be drama on funding coming up later this year with regards to Ukraine Funding. I would not underestimate Trump after what happened in 2016, and Trumpism seems to be currently the dominant faction within the Republican party currently.