That's not how peace treaties work, but whatever.
In any case, Russia will not accept that "strong security guarantees" are put in place before such referendum took place. Because they know if you ask the Ukranians once the war has ended and there's a EU-led security force in the territory (also part of the statement), they won't vote in favor of giving Russia the territory.
So I reiterate, they know those two things are non-startes for Russia.