I find risk slightly bigger when you encrypt your private data with the product of the company and store that encrypted data on servers of the same company.
Why: because if they have some backdoor now or plans to introduce it in future, they have all the time in the world to apply that backdoor to your data. Without you knowing it.
If it was backdoored, many people would be calling that out.
In theory. And not necessarily soon.
Don't forget the context of this thread: we compare bitwarden with keepass, which does not offer to you your password base on their server side.