Wash it, dry it thoroughly and polish it. Any bug splat will go moldy if left and can mark the finish. Change the oil before storing it, even if it's been done recently, so the oil in the engine is pristine and unused.
ACF50 all over it is definitely a good idea and I'd spray all external moving parts and joints (bar lever pivots, foot control linkages, swinging arm pivots, shock mounts etc) with a good silicon-based penetrating oil so no damp can settle between mating surfaces.
The only issue you might face after a three year lay-up is perished fork seals. They can harden and go brittle when left unused for long periods. A lot of people had that trouble during covid, myself included. The dealer said after lockdown there was a run on fork seals.
While it's good to keep the weight off the tyres, if it's possible, it's even better if the bike is wheeled around occasionally, the suspension pumped and the brakes worked. Atmospheric moisture is very good at condensing between discs and pads, especially in an unheated garage.
Not a bad idea either to put a cover over it to keep it free of dust and cobwebs and fly spots.