Is there a single source that is not manipulated on these topics? For example in Ukraine, it is very obvious that both western mainstream media and Russian mainstream media are little more than propaganda for their respective camps.

The good thing with Wikipedia (the English version in particular) is that both sides try to manipulate it, in addition to those who really want to say the truth, so in the end, it is relatively neutral. And if you want to go further, there are citations, which is maybe the most important aspect of Wikipedia compared to traditional media, including encyclopedias.

Wikipedia is not perfect, but it does its best to resist manipulation: citations, all activity is recorded and publicly available, etc...

Non-English Wikipedias have more bias, because they are smaller and also because unlike the English version that is used worldwide, even by non-English speakers, the non-English ones are often tied to specific countries. For example, I think I remember seeing the Arabic Wikipedia as being explicitly pro-Palestine, I guess the opposite is true for the Hebrew version.