And I expect that if Trump blows out Harris by 10 points, the left won't riot either.

Disagree. 2017 is the evidence, with Inauguration Day riots after Hillary! lost. That's why I can say no matter what, in any Trump victory scenario, the left riots.

What if Trump loses by 1-2 points, in a close election? What does the right do? Anything different than from when Trump lost in 2020?

Again, depends how it goes down.
Recall that in 2020 we all went to bed thinking Trump won, only to wake up the next day seeing Georgia flip to blue and hearing stories of "water leaks" at ballot stations:

abcnews.go.com - Pipe bursts atlanta arena causing hour delay processing

A pipe burst in State Farm Arena in Atlanta on Tuesday morning, causing a four-hour delay in processing election ballots, according to deputy Secretary of State Jordan Fuchs.

Now this "burst pipe" turned out to be a...leaky urinal...but was reported as a burst pipe. What's never been explained is why a leaky urinal that somebody sponged up would cause a 4-hour delay.

So during counting, let's say this scenario plays out: Ballot counting is going on in Pennsylvania and the results show a Trump lead. Then at 3AM, the power suddenly goes out in several ballot processing facilities across the state. At 4AM the power comes back on and Harris has the lead and is declared the winner. I can see the right not liking that case.