This shows, from inside the crankcase, the oil drain (red circle) and the breather gallery to which the breather hose is attached (green oval):
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This is your picture of the PCV compartment with the drain circled in yellow:
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I do not understand how you got that upper crankshaft main seal out without either removing the crankshaft, or destroying the seal. If it was loose, oil mist will blow out past it due to crankcase pressure. I suggest you fit a new seal, ensuring that it is tight in the crankcase.

That upper main bearing (a ballrace) looks normal in the picture. If it rumbles or has radial slack, it needs to be replaced. The oil seal relies on the crankshaft remaining precisely in the center of that bearing: oil seals cannot tolerate much radial misalignment, or eccentricity, of the shaft. A bearing with slack could cause your present problem. However if the bearing does not have slack, nothing is gained by replacing it.