Bring some ammo
Bring a GPS
Put some fuel in your vehicles
Stay sober (hardest of all)
None of these were problems. Instead:
1) The airborne that took Hostomel expected help to arrive within literal hours.
2) Instead it took more than a day for the mechanized forces driving down from Belarus to arrive. Why? Because there were so many of them they literally spent hours waiting in traffic jams on a two lane roadway surrounded by dense forests on both sides.
3) Miraculously, the paratroopers managed to hold out an entire day, surrounded by the bulk of Ukraine's forces in the North collapsing on their position. The mechanized forces reached them, and helped them secure Hostomel. But by this point it was too late. The runway had been damaged, and hundreds of further reinforcement flights were cancelled.
Key factors that ruined things for us:
1) Americans warned the Ukrainians about 24 hours ahead. This allowed them to evacuate their army and air bases. Russian missiles fell onto a bunch of empty locations.
2) The dense forests on each side of the road, that created traffic jams. One of the things I read, is that if we do it again, we will cut a path through the forest 100 meters wide on either side, to prevent Ukrainian ambushes and increase throughput. Helicopters equipped with suspended electric saws will help.
3) Earlier army reforms had produced an army format totally unsuited to this type of warfare. We entered the war using Battalion Tactical Groups, but have now effectively reverted back to divisions and corps. The independent battalions were well equipped in terms of firepower, but were very thin on men. As soon as they lost a hundred or so men, their combat effectiveness fell to approximately zero.
I could keep going and going, but having a GPS and staying sober were certainly not the main concerns.
Ukraine still has weapon factories? I really don't get it...
Like Nazi Germany circa 1944 - they have moved many things very deep underground. Many Soviet manufacturing facilities were built in hardened fashion, to resist any strikes. An example is OKB Yuzhnoye, the builder of Soviet ICBMS.