Your link confirms that the cuts are illegal.
For good measure, I pasted it into Gemini as you requested, and this is what it said:
> Me: Does this say that the president is allowed to prevent distribution of funds from NSF without congressional approval: https://www.aip.org/fyi/trump-proposes-deep-research-cuts-ne...
>
> Gemini: No, it does not. [etc.]
> > The request PROPOSES $4 billion for NSF, a 54% cut from the fiscal year 2026 enacted level. The amount echoes last year’s proposal of $3.9 billion, which Congress soundly rejected, FUNDING THE AGENCY at $8.75 billion.
The current FUNDING is $8.75b, not the $4b he PROPOSED. Here's the wikipedia. Hope this helps.