Baryon acoustic oscillation measurements
They also used the observations from (2) - DEI (Dark Energy Spectroscopic Instrument): This tool is like a super-accurate balance scale that can measure how much mass and energy are in the universe...
Technical definition
Baryon acoustic oscillation (BAO) measurements exploit the periodic patterns of galaxy distributions resulting from the expansion history of the universe, which reflect changes in the density fluctuations due to matter and radiation interactions.