100% and the way Russia is fighting this war is very similar to the U.S. in Vietnam: a lot of self-imposed restrictions, giving up strategic objectives in exchange for lower casualties, superior firepower but against an enemy that is more determined. U.S. didn't bomb North Vietnam near the Chinese border to avoid a Chinese intervention like Korea, but all the supplies were being shipping in from that border.
IMO the retreat from Kherson + mobilization are clearly signals that Russia is hunkering down for a multi-year war of attrition, rather than a focus on short term gains and capturing territory or any negotiations. IMO the way Russia is probably hoping to win now is outlast Ukraine over a multi-year period. If Ukrainian society collapses internally, it doesn't matter if they are holding on Kherson or not.
However, as cruel as it sounds, Russia would really need to make life in Ukraine unlivable to exert maximum pressure on Zelensky's government, and force him to push for larger aid packages, both economic and military. Ukraine as no economy, no MIC/factories producing lost equipment, and no additional bodies to mobilize, once aid is gone, its all over. Cities like Kiev, Odessa, Lviv, etc. can't be left untouched.
Interestingly, North Vietnam had a population of ~25 million during the Vietnam War and it seems despite the casualties, there was never a manpower issue. Though the amount of aid North Vietnam received was ridiculous, Mao almost gave the shirt of his back to support their war effort.
The analogy is close and it is in my mind. There are however critical differences. The Vietcong is more like the LPR and DPR. There isn't as much jungle to hide in. Ukraine is a highly industrialized country heading back to the stone age. Ukrainians are not the Vietnamese who are toughened living in an agrarian society without conveniences. Huge difference between smartphone social media addicted millennials who whine when their wifi is cut off vs. those toughened farmers and peasants who can dig and live in deep tunnels that can survive bombing from B-52s.