I'd say buy a decent 32" 4K display. I have no regrets switching from a 5K 27" 60hz to a 4K 32" 144hz. 3008x1692 equivalent res and everything looks great (LG 32GQ950-B). 60hz is so painful these days, too, and Apple's 5K displays are overpriced, and the older LG models just had too many issues (I had 3, and all had problems to some degree).
I'd say buy a decent 32" 4K display. I have no regrets switching from a 5K 27" 60hz to a 4K 32" 144hz. 3008x1692 equivalent res and everything looks great (LG 32GQ950-B). 60hz is so painful these days, too, and Apple's 5K displays are overpriced, and the older LG models just had too many issues (I had 3, and all had problems to some degree).
For me, it would be a no-go to switch from a Retina resolution to a non-Retina resolution. That would always be more important to me than having more Hz. But that's also why I'm waiting for a monitor with 220PPI, 32” & 120Hz or more.
I’ve been using 32” 4K for several years now. There’s no question that 27” 5K is sharper because of course it is. But when using the 4K 32” set to 3008x1692 it offers more real estate than the 2560x1440 equivalent on the 5K display, and still looks very good indeed. And I’m picky. I couldn’t go back to the 5K display. Size and refresh rate is leagues beyond, and sharpness is still very good, if not as good as the 5K.