Probably not what your looking for, but my two cents is that the 3090 will be very relevant for ML workloads for years to come. Even the GTX 1080 is still being used for local Stable Diffusion models, and considering that the 3090 has AI-specific hardware in it, I think the card is a pretty safe bet.
Just try and get it as far under MSRP as possible. Nvidia has an enormous GPU surplus now, do a little shopping and see what you can find.