Re-read that memorandum, please. Who and what "guarantee" there?
OK...
The memoranda, signed in Patria Hall at the Budapest Convention Center with U.S. Ambassador Donald M. Blinken amongst others in attendance,[3] prohibited Russia, the United States, and the United Kingdom from threatening or using military force or economic coercion against Ukraine, Belarus, and Kazakhstan, "except in self-defence or otherwise in accordance with the Charter of the United Nations." Russia breached the Budapest memorandum in 2014 with its annexation of Ukraine's Crimea.
en.wikipedia.org/wiki/Budapest_Memorandum
... and then came the full-scale invasion.
We would prefer friendly independent poland as a neighbour
And we would be absolutely delighted with a friendly, still-in-one-piece, Russia as a neighbour. You are the biggest Slavic country with the largest nuclear arsenal and territory in the world. You should be our big brother not a bully. So you better mend your ways or Курица не птица will get angry and lay some eggs from which Żółkiewski, Chodkiewicz and Piłsudski may hatch. ;)
ended Ukrainian neutrality and turned it against Russia
Oh, so it was Ukraine who invaded Russia?