It is scary to think about, because if someone is able to get your one major password, they will have access to all your passwords.
It's not a fool proof setup ofc but IMO it's still better than getting locked up/resetting frequently.. Especially, if you're like me who has hundreds of accounts I dont use everyday lol
However, if you tend to slack on your personal cyber security then it'll come and bite you lol. Keepass for instance stores the database in your device hence you need to keep it clean at all times. A good tip would be to compartmentalize risky stuff to non-risky stuff e.g. get a device that doesn't connect to internet or at least don't do risky stuff on the same device you do important stuff.
I would also suggest enabling 2FA whenever possible so you have a second layer of protection. However, you must keep it in a separate device to maximize security. In a sense, this is also compartmentalizing -- if the device where your password manager gets compromised, your 2fa is likely to be fine as it is in a separate device/environment.
I don't encourage saving passwords with third parties like this because it's more risky than it being lost in your hands than to some kind of hackers.
Have you thought of what happened to Laspass? That's just to tell you that none is save expect your own personal backup.
Note that keepass is a FOSS that stores data locally -- on your device. LastPass on the other hand stores them on cloud hence the data leaks weren't surprising to me. I wouldn't trust a stranger to held such important data either.