It's difficult question. Assume 5k2k 40inch (U4021QW) vs 8K 32inch (almost same height); 5k2k is great aspect ratio for single monitor setup, but dpi is moderate. 8k 32inch is too much dpi for 200% HiDPI. 8k 40inch is sweet spot for 200% but it's too big for monitor. Maybe I'd take 8K 32inch and use with 250% HiDPI, if prices are same.
