74% of Ukrainians support fighting Russia even without U.S. assistance. A significant majority—59% of respondents—also believe that Ukraine can defeat Russia on the battlefield
only 6% of respondents said they were willing to make territorial concessions regarding areas occupied by Russia after the full-scale invasion in 2022
Additionally, 70% of respondents are against lowering the mobilization age,
Original article is paywalled, quotes from https://ukrainetoday.org/74-of-ukrainians-ready-to-resist-russia-without-u-s-aid-support-zelenskyys-actions/
You’re underestimating the difficulty in suppressing an insurgency. Even if the uniformed forces are defeated, that would only be the beginning of Russia’s challenges in controlling that territory. For a recent example, review the US in Afghanistan. Thousands of lives, billions of dollars, and two decades only for things to revert exactly to what they were before. The US wasn’t even trying to annex the territory, in the traditional sense.