We have been going at this topic for a while now… the robust import of 1Password data to Bitwarden.
There are threads here, and here. There are other threads on the topic if you search for them.
We’ve had one reply from a Bitwarden developer that I’ve seen to date suggesting that there is work being done or that it will be done at some point in the future. No timeframe offered yet that I’ve seen.
Cheers.