Just wanna add my stupid experience)) But it 100% reflects all sympthoms and visual issues discribed above)) So I was trying to alighn 2align two objects by their origins, I've set both origins 'to geometry'To Geometry, then selected both objects and tried to alighnalign them on X and Y axis by pressing 'S -> X S, -> 0 X, 0 and S -> Y S, -> 0 X, 0.
I don't know if the hot keys were wrong or they changed from the version of the tutorial but everything dissapeared)))disappeared. Then I understood that objects just collapsed in ONLY 1only one point. So, so I was able to see them in the outlinerOutliner and in 3D viewport actually (but. I thought it was the origin point, but it werewas my objects scaled down to 1one point);.