Montana perpetually held this status from around 1952 to 2016, but nowadays it seems that last bastion of elasticity and ticket splitting has finally been nationalized out of its independent streak, quite regrettably I might say. Besides the two that you mentioned, NE-01 could be a possibility if Lincoln continues growing, but I don't think that many other states around that margin of Republican lean are elastic enough to be genuinely competitive, and are generally in trend limbo (MS, SC, etc).
I’m not sure if that’s definitively true. It appears that in 2020 polls missed many Republican-leaning voters who were probably inspired to turn out by virtue of Trump’s presence at the top of the ticket, and Democrats didn’t have a single incumbent statewide officeholder who was running for re-election to his/her existing office (unlike 2016 & 2018, when they had their incumbent governor and Senator running for re-election, respectively, which gave them the incumbency advantage). Some downballot Democrats did outperform Biden, but they didn’t do so by much due to the increase in Republican turnout. It remains to be seen if Republican turnout levels in 2020 can be sustained if Trump is not at the top of the ticket or has his standing with the Republican Party diminished significantly (and the popularity of the incumbent governor and Senator up for re-election in 2024 may also shape how that year’s election turns out).
