Gary Shapely hasn’t confirmed anything.
He’s made allegations, he might have confirmed his allegations by stating them to the committee but that is not confirmed that his allegations are correct.
The BBC have a far more complete report, including small details that Weiss was a Trump appointee and many of the alleged ‘delays’ and ‘blocks’ occurred prior to 2020 during the Trump administration:
https://www.bbc.com/news/world-us-canada-66252781.amp