I would recommend a pragmatic approach. Military doesn't draft military contractors. I would recommend learning a REMF trade (REMF means Rear Echelon Mother Fucker) like repairing rifles (these guys are employed but rarely drafted, and if drafted they become armorers, so even if put on a frontline unit, you are only at risk of indirect mortar or rocket fire, unless the front line is overrun). Take electric courses, get a forklift licence. Then, take a part time job for a company that is hired by the military, but in a extreme rear position (if ukrainian, take a job in Lviv).
Why? If you establish a work history, and get recruitment papers, you likely can get rehired faster by the private company who is likewise surging in hiring due to the military expanding, than they can field you in the military. Once they see you are a military contractor, they will leave you alone. You can do stuoid stuff like move a forklift around a base moving bed frames (I've seen this in Iraq, all the guy did for a year, for some 600 men).
The more qualifications you have for setting up a base, the more likely you are in being selected. I have a skillset I never use in machine blueprint reading, multiple electric courses, welding and plumbing, and I got them prior to turning 28 (initial high point for the draft in the US), and kept it up till age 35 (upper limit for joining in the US Army), and now after seeing Russia and Ukraine obsessed with drafting old guys, I'm likely going to take a official gunsmith course just to earn that armorer position. I'd rather not be in a trench wearing a catheter in WW3 as a old man, put me in a bunker as a essential rear worker instead. I'll repair the guns and wire up the electricity to the generator. Just leave me alone otherwise. Watch me stock a warehouse. I have so many OSHA qualifications.
