Shooting blind here. What camera/format are you shooting your stills in? What computer system/OS are you using ? What monitor have you got - is it a true HDR monitor in other words?
I'm on Windows 11 Pro, I have BenQ monitors (SW270C, SW240). No HDR monitor at the moment, it's a jungle of misinformation that I haven't sorted out yet, especially that I don't want to spend to much on that at the moment. I could, as you do, use LR and/or ACR + Photoshop to create various formats of HDRs images, but they would be trash down to SDR on Facebook. I haven't checked all my option yet.
I have a Nikon D610, and I shoot 14 bit raw. But since I rarely end up using even edited raw, I'd like to learn which sort of HDR file is more compatible with Resolve.
I saw in another post from you that Resolve may not be the best choice when starting from "HDR Image".
I'll give a couple more clues of what I intend to do.
First, all HDR video I'll create must adapt to SDR display automatically, maybe with the potential to edit (grade) the SDR version. Something similar to what can be done in LR with gain maps.
My workflow will frequently involve: focus stacking, image dependent gamut mapping via ICC style color management (DevLink profiles), compositing, and more. Resulting, in various potential formats, of which, 16 bit tiff files with linear ProPhoto RGB colorspace will be the most likely. I almost forgot, these image will be mostly 6000 x 4000 pixels up to 12000 x 8000 pixels. The idea is to be able to pan and zoom over all that space as I need, through a normal 16:9 viewport, HD, 4K, etc.
My goal in all this is to provide the best HDR quality that I can, especially for colors. The HDR standards that I've seen require, at minimum, 1000 nits, 100% DCI-P3 displays, and so that's my minimal target, but if possible, a little better, I don't know enough yet to decide.
Thanks