I agree, short term situation would be disaster. But IMO, Germans won't do serous offense.
Germany needed to knock out Franc and Britain before US arrives on Western front. So Germany has no luxury of time.
Everybody expected Germany will be almost lost if US bring significant force.
Was Bolsheviks doomed if B-L hadn't signed ?
Just retreat to Moscow and wait Germany start to loose in Western Front. After Germany fell claim all Russian Empire land, maybe except Congress of Poland. They will be at least formally at War, thus appears as fulfilling their obligation.
Or Bolsheviks afraid that Germany occupying Russia then making separate deal with Western Allies?