Use the "passwords" feature to check if one of yours is compromised. If it shows up, never ever reuse those credentials. They'll be baked into thousands of botnets etc. and be forevermore part of automated break-in attempts until one randomly succeeds.
I've heard great things about Bitwarden, Vaultwarden, 1Password and Keepass, although the latter may fall out of preference rapidly. Some also recommend the Apple Cloud key storage. Call me a stickler but I haven't trusted Apple security since the Fappening, even if it was the victims' fault for not using 2FA