They were prevented from buying out ARM.

They can always license their IP and make products out of that.

Some of their systems most likely have such chips already in them.

It wouldn't surprise me if they are looking into making their own RISC-V CPUs, since their coprocessor already is build on it already. They also are porting CUDA to RISC-V (specifically RVA23 is their minimum supported) so it would somewhat make sense to do it.

This will sound like I'm joking, but I'm not. It seems like with this administration, having the regulators reverse their decision wouldn't be that hard, especially with a "donation" to the ballroom or something along those lines.

I don't think the UK is interested in a ballroom. The UK blocked that deal, not the US.