True.But Germans need to be thinking less about that "Cheaper Price" and thinking
Quite. They have to understand that they don't run the continent and that attempts to cosy up to vicious dictatorships in order to get cheaper oil than neighbouring countries so they can undercut them is something they won't get away with again.
And of course there's no chance there'll be oil sold directly to western democracies by ruzzia for the foreseeable future, certainly decades, and nor will trade with ruzzia return to pre-war levels for a long time if ruzzia remains within its present form and borders.
There's also the issue of ruzzian agents and collaborators in mainland Europe. Their names will almost certainly end up in the public domain with no chance to hide them behind data privacy laws. France and Germany have perhaps the most exposure to this among larger countries and sad to say, there are certainly ruzzian agents or agents of influence in other countries, including PL.
that is a mistake all Western countries except the USA made
This is true, and we may well pay a high price for being penny wise and pound foolish over the years. Prior to 2022 only a few NATO states paid more than the amount expected, the U.K. and Poland among them, however there were still defence cuts in both places. The U.K. ones were brutal but done carefully and the British Army is certainly still the best in Europe, despite many rather short-sighted changes.