Talk me out of this because it has been creeping into my head for the past couple of months. Setting aside all other CR considerations:
An election that results in more of the same policies is more likely to mean Ukraine continues to lose slowly while Russia's economy and military continue to be substantially depleted. Put another way, will a Harris admin approach this differently and with much greater resolve and courage than the current admin? I haven't seen much to suggest otherwise. This increases the likelihood of a meaningful Russian breakthrough at some point, but even without that, Russia is able to take more territory and Ukraine loses more bargaining power than it already has for when the time comes to settle this.
An election that results in a new admin where they are determined to end it now could result in significant and terrible concessions for Ukraine, but given the person in charge is unpredictable and highly sensitive to how he is perceived, the risk that it is seen as a "weak deal" would be an effective deterrent to giving up much to Russia and could actually end up strengthening the USA's resolve vis-à-vis the president and, therefore, Ukraine's bargaining power. Again, this is highly dependent on capriciousness, so it's more likely to result in extremes. But, if it is appearing increasingly likely that the alternative admin would continue down the path of slow decline, then the chance of the more favorable result for Ukraine might actually lie with the counter-intuitive admin.