This claim is true.
According to the National Park Service, last updated June 11, 2025, the most notable post-Vietnam parade to take place in DC was 34 years ago during the June 8th, 1991, during the Desert Storm parade, also known as the National Victory Celebration. This parade featured approximately 8,000 troops, accompanied by tanks, missile launchers, and aircraft flyovers. A June 9th, 1991 LA Times article corroborates that there were 8,000 troops in the parade.
According to NPR, a June 15th, 2025 article states that over 6,000 troops marched in the parade, also accompanied by armored tanks and artillery vehicles and aircraft.
The NPR article discusses the politicization of the parade, as well as a counter-protest movement taking place on the same day. It should be noted that both the archived 1991 LA Times article and modern coverage of the respective parades mention that concerns were expressed by some about the excessive cost and military glorification of the parades, although this does not seem to have resulted in inaccurate reporting of the size of the parade.