I self-host my mail server and use an IMAP+SMTP client to talk to it - I don't use something like gmail. $work uses gmail and the web ui frustrates the hell out of me (and I pity anyone whose only experience with a native email client is being paired with gmail, because their IMAP implementation makes it rather painful!).
For password manager, 1password has a native app and browser extensions that talk to that local native app. There are browser only ones too, but I prefer the native app integration because it shares unlock state between all of the extensions and the full desktop client all in one go.
But you're right, you can't have change without things actually changing. It's a tradeoff between convenience and what you're used to, and the benefits of what you get from changing. For me, for now that ends up sitting on the side of macOS. For others, that might be Linux or even Windows. I don't think any of those positions are wrong, it's all about what works for each person.
Humans adapt. It's what we do. Yet so often we mistake wants for needs.
Subjeectively, being attached to an email client feels odd to me. That's what the brower is for; same for a PW manager. If Bitwarden has a client, I wouldn't even know. The browser ext works just fine. I used to use LastPass.
Ya can't have change without change. It's not necessarily easy. But it's always true: No delta, no glory.