I'e seen that some want it to host their own LLM. It's far cheaper to buy DDR5 memory than somehow getting 100+ GB of VRAM. Whether or not this is a good idea is another question
Also sourced from Chiphell, the Radeon RX 9070 XT is expected to command a price tag between $479 for AMD's reference card and roughly $549 for an AIB unit, varying based on which exact product one opts for.
This sounds reasonable IMO. After all, there is still room for a cheaper 9060 / 9050 series.
Something like the 6600 / 6600XT / 6650 XT would fit in your budget.
But my recommendation is to wait maybe a month or so - the next GPU generation is just around the corner. It takes a while for the cheaper GPUs to arrive, but this might be able to find some nice deal or a good offer for a used GPU.
If I understood this correct, there would be some options that could improve the performance impact, for example limiting the time range or building indizes. But apparently, it isn't of a high prio for the devs.
VA-API is Video Acceleration API