> There is no definite way of isolating the importance of the .com but it is likely to have played a part. Our domain authority also increased meaningfully.

How is it possible to conclude that "it is likely" given there aren't any evidence to support that?

After reading the article my takeaways are that a) the agency you hired might have helped you with SEO much more than changing the domain and b) the success you had after the migration don't correlate with the domain change, but more with your distribution.

To be honest, I'm not really convinced that purchasing the .com has played a role in your success after reading this.