Most wars are won based on attrition, I.e., based on who can outlast the other. Absent NATO forces joining Ukraine, Russia has overwhelming resources, which will allow them to win.
RuSSia is a degenerate 3rd world shythole country. It cannot even make an automobile now. (Famous car reviewer making fun of the new Lada straight off the assembly line: https://www.youtube.com/watch?v=6fHnAbeLZb4&t=1026s)
Most of its weapons are filled with Western software and electronics. Or they WERE. And even then, they didn’t work as advertised just as always.
Every day more aid is pledged to Ukraine and they get stronger and stronger while RuSSia gets weaker and weaker. (The REAL Russia according to an ACTUAL Russian: https://www.youtube.com/watch?v=TTJgzjEqcRM)