The only way this is not a coffeelock is that it is not Warlock spell slots being used to make the sorcery points that are being converted into Sorcerer spell slots. Here is the description from
Geek Native:
Obviously, the method you are using differs slightly.
@Hohige variant:
This is obviously coffeelocking. If you avoid a long rest, you are coffeelocking. In general, taking multiple short rests while avoiding a long rest in preparation for an event is a sign of some variation of coffeelocking. Heck, the Sim making spell slots
at all from Flexible Casting borders on coffeelocking.