I think you're looking at this differently than I am. I'm looking at states that were close in 2016 versus states that are close at present, and the effect that the electoral votes of those states would have on the overall outcome of the election.
To that end, the margins in Washington, Oregon, and California are irrelevant. They all went to Clinton & Biden by insurmountable margins in both elections. They aren't even in the pool of consideration for this round of game theory
In 2016, there were 2 states with a margin of less than 1% difference: Michigan (0.3%) and Wisconsin (1%). Clinton had 227 Electoral votes. Michigan is worth 16, and Wisconsin is worth 10. If Clinton had sought a recount of those two states (one in a close race that would have benefited her if they flipped), she would have gained a total of 26 electoral votes, putting her at 253. That's still below the 270 threshold needed to clinch the presidency. The next closest race was Pennsylvania, which has 20 EC votes, and was at a 1.2% margin, and 68,000 votes.
In 2020 (to date) there are four states with a current margin of less than 1%: Arizona (0.1%), Wisconsin (0.7%), Georgia (0.3%), and Pennsylvania (0.7%). In total, they are worth 57 Electoral votes, which would be enough to win the presidency. I don't think there's any reasonable chance of that happening, but I'm treating both elections with the same logic.
So, in 2016, the borderline states didn't have enough votes to gain Clinton the win. It wouldn't have been worth her while to challenge, as it had no chance of changing the outcome. In 2020, the borderline states DO have enough votes to gain Trump the win. Thus, it's worth his while to challenge them.
The complication here is that there are still a fair number of absentee ballots not counted, due to COVID and the USPS. Like I said, I don't see the final outcome shifting sufficiently to give Trump a win, but I can see the rationale of challenging those counts.
I've lost track of where he's challenging though. I'm pretty sure he's challenging in states that make no sense to challenge at all.
ETA: Forgot to include the references.
2016 election results
2020 election results (to date)