It had a vast technological and numerical advantage.
The planes were better but their actions were limited by Ukrainian anti-aircraft defense using western systems and the Russian tanks were definitely not much better than Ukrainian ones, as we could very well observe during the initial phase of the conflict. As for numerical advantage, the initial Russian invading force was actually smaller than the Ukrainian army, which from the very beginning doomed the invasion to failure. You need to have more soldiers than the defender to successfully invade a country - Russia didn't have this advantage.
tanks only arrived after Kherson was liberated.
Wrong again. Kherson was liberated in November 2022, Poland send T-72s (over 200 of them) in April 2022 already.
how little of promised aid has ever actually materialized
That's what annoys me--people downplaying the amount of aid that Ukraine received.
So, let's see what Poland alone gave...
- 310 T-72 and PT-91 tanks, serviced, modernized (engines and optics) and prepared to fight (Ukrainians themselves were shocked and said that the tanks looked like they were brand new, out of factory, and said they were like Mercedes compared to Ladas in comparison to their own machines);
- 14 Mig-29 fighter planes
- 11 Mi-24 assault helicopters
- 14 Leopard 2A4 tanks
- 400 BMP-1 AFVs
- 50 Rosomak AFVs with Hitfist-30 turret
- 54 self-propelled Krab howitzers
... plus older 2S1 Goździk self-propelled howitzers, tons of other artillery with trains full of ammunition (BM-21 Grad, Newa-M, Osa, Wega, 2B9M Wasilok, LM-60, ZSU-23-4 Szyłka), anti-tank and anti-aircraft launchers (including Pioruns), rifle ammunition, fuel, explosives, even military rations - trainloads upon trainloads of stuff that Ukrainians were able to use right away, too many things to even mention and the official list is vastly incomplete. A lot of this stuff is still classified but very careful estimates say that Poland passed about 5% of her GDP to support Ukraine.
And that's Poland alone!
If anyone claims that Ukraine would be able to defend herself without aid against those "incompetent, drunk Russian grandfathers", then he's a raging idiot.