You have a nice wartime item that you know to be such. The problem with this type of cancellation is that it does not show when it was cancelled. There is no way to tell whether this item was sent during or after the war - once that has ended - unless someone dated the item.
This type of cancellation is a common occurrence as you appear to have experienced. See this thread: http://goscf.com/t/3853&whichpage=1
It is likely the marker monkey was your local postman and not a Ukrainian official.
Much of Ukraine is not occupied and mail is still being sent from and received in Ukraine, but also in Russia. Postal services outside the war zones are close to normal. So, these are unlikely to be a rare use. Ukraine is issuing stamps for every major event in the war. Ink and printing equipment do not seem to be in short supply. There is no reason to assume this is any different for mail sorting equipment. Rather than being due to a lack of equipment, you might argue Ukraine's Post Office will do its best to service mail as well as it can.
Most collectors will consider pen-cancelled stamps damaged. However, as this is quite a normal occurrence, maybe it should be accepted as a genuine cancellation Collectors, often, are very conservative. So, it may take some time before they will accept these as normally cancelled stamps.