IME, because of pay, they have a hard time retaining "senior" talent, eg Nvidia, Chainguard, Amutable, Lambda, etc etc etc all have lots and lots of senior+ Canonical engineers. Especially in the age of AI, I think this is a "people-strategy" mistake.
The application process is very long and you absolutely lose great candidates because of it. Salaries are not US-tech competitive, but absolutely are Central/South America and Europe competitive. Lots of great Brazilian and Polish engineers, for example.
Also I have never seen a post on HN, Reddit etc about Canonical/Ubuntu that doesn't complain about hiring process. I think it does a pretty incredible amount of damage to the brand.