I ended up with the LG 32UL500-W (https://www.rtings.com/monitor/reviews/lg/32ul500-w), for about $300 US.
My conclusion was that trying to get a higher refresh rate 4k monitor, or even higher resolution, or OLED or anything else, made it 2-6x more expensive. Prices for these features still have a _ways_ to go before they're affordable.