On the cotter question, there are a few things you can check.

Spindle: are the two flats on the spindle parallel? Fnot, there’s your problem. Solution: new spindle.

Cotters: compare the two cotters. Are they the same diameter (this may not actually matter, but…)? Are the tapers the same (this is crucial!)? To check the tapers, hold the two cotters together, taper to taper, threads opposite one another; and measure the combined thickness at two or three places. If they vary, there’s your problem.

If spindle and cotters pass the above test, then you’re dealing with an installation problem. One of the cotters isn’t seating properly.

I suppose it’s possible that the hole in one of the crank arms is oblique, but I doubt it.

On the beer question, this is a matter of taste. Stella Artois is a perfectly acceptable rendition of the north German style of Pilsener, usually called Pils. If there is a difference between Becks and St Pauli and Heineken and Amstel and Molsens and Corona and Stella and a hundred others, I haven’t detected it. They are not my preferred type of beer, but even I'll admit they taste better than cat piss. If they are not to your taste, don’t order them. Try one of the Munich beers (but avoid the Pils, regardless of brand), Belgian beers, and English beers.