1973 war.

But the greatest Soviet involvement came in 1970, to bolster Egypt with improved AD.
Of course. Soviet weapons would've been delivered faster and in greater quantity. They were also cheaper, and long term credits were available. (Of course, one problem would've been loss of access to far more lucrative arab markets, notably in Iraq and Libya. Without US $ Israel might've found it to tough to pay for massive imports of soviet arms.)There were some quality issues vis a vis western weapons but they would do. Arab failures weren't mainly due to those issues.
Right. The Soviets could've encouraged Israel to go very far. Dayan didn't want to occupy arab capitals but Soviet encouragement might've led to much of the arab world being overrun, including oil producing areas. In theory, that might've compensated for alienation of the arabs due to a pro-Israel policy.
But the Soviets no doubt felt this would've been a risky gamble and it was more prudent just to back the arabs.
Well, not entirely, as the '73 oil embargo indicates.