need some advice about upgrading

Hello all,

My current sim rig runs MSFS2024 on a 7800X3D + RTX4090 + 96 gigs of ram.

I have in my possession my old 64gb (2x32) kit of ram that I previously ran with the above setup. (Luckily I bought the 96 gb kit before the prices went up...)

Given the above...

My work computer is in need of upgrading. I built it circa 2017-2018 from some spare parts....for example even though it's a desktop/mid tower PC, I put an Intel T-class mobile processor in it (i3 4130T to be precise). It has a paltry 4 GB ram and runs Windows 8.
My thought is, since I have the 64 gig laying around, I might as well build a new work machine around those sticks. I'd like to do it fairly economically as I don't need a powerful rig at work. So, should I:

1) build a lower-end AM5 setup with say a 7700X or similar
2) take my flight sim 7800X3D and put it in the work machine, and buy a 9800X3D (or similar....X3D2?) for the sim rig (I would have to buy a motherboard for the new work machine of course)

Or, can you think of another option that might be better?

Thanks, I value your opinions on these matters...