1- NSF budget is about 10 billions, I always had in mind that it is much more. That's about 0.17% of the total federal budget. If we include DOE R&D funding and NIH we will get to 1%. This is the funding for most of research in science in the US. Seems like not a great area to achieve huge reduction in deficit.
2- Even if we ignore the whole point of DEI and say that we need to end support for some of the projects. You do take your time and evaluate projects that needs to take action. You don't stop all the funding and pause critical support for projects and cause huge problems on medium and long term. And it also hurt the reputation of the country and its competitiveness.
3- The current NSF director was actually appointed by the current setting president in his first term.