I skipped spds after seeeing people complain of knee problems and then switching to Times and being OK.
I had Atacs but then I switched to Look 4x4s, which are like eggbeaters but they always had two sets of bearings, like the current crank eggbeaters.
They float really well, but I found it best to ensure I peddle with a ruler straight back, titling from the pelvis, and just pumping the thighs up and down, with the lower legs just following, rather than pushing down through the knees. I found that puts loads less stress on the knees whilst improving efficiency.
You could maybe do also with going to a good podiatrist in case you could do with your shoes having footed to cant your legs so they run ‘straight’ like skiing.