Yes, the US is a very different country from the U.K., which is why we have to examine them separately. We cannot base our views on terror threats in the U.K. on information about terrorism in the US.
”Between 1994 and 2020, there were 893 terrorist attacks and plots in the United States. Overall, right-wing terrorists perpetrated the majority—57 percent—of all attacks and plots during this period, compared to 25 percent committed by left-wing terrorists, 15 percent by religious terrorists, 3 percent by ethnonationalists, and 0.7 percent by terrorists with other motives.”
www.csis.org/analysis/escalating-terrorism-problem-united-states
What this doesn’t reflect are the # of victims though:
“In analyzing fatalities from terrorist attacks, religious terrorism has killed the largest number of individuals—3,086 people—primarily due to the attacks on September 11, 2001, which caused 2,977 deaths.10 The magnitude of this death toll fundamentally shaped U.S. counterterrorism policy over the past two decades. In comparison, right-wing terrorist attacks caused 335 deaths, left-wing attacks caused 22 deaths, and ethnonationalist terrorists caused 5 deaths.”
There is also this graph that shows right wing terrorism is more of a threat in the US than religious based terrorism (includes Islamist).