Diffraction softening varies with aperture, sensor size, and photoreceptor size. For instance, on a full frame 24MP camera, I don't run into diffraction until F9, and even then it's fairly minor, and a trade-off I'd want to make (focus stacking doesn't work all that great on moving objects).It happens faster with smaller photosites, but, if those are associated with a higher pixel count, and you're judging by print quality, not pixel-peeping, it's less of an issue.

If you're got an Android device, check Jon Sach's DoF https://play.google.com/store/apps/details?id=me.jonathansachs.dof (free/no ads). Download the 'reference manual', it's spectacularly useful.

There's also a Windows version at https://www.dl-c.com/DoF/, and the reference manual (for both) is here: https://www.dl-c.com/DoF/DoF_Reference_Manual.pdf