A realistic plan

An hour, once.

The order

Install a manager. Secure the email account with a strong unique password and two factor. Do banking next. Then fix reused passwords on anything holding money or identity.

Let the manager generate new passwords as you naturally sign in.
Perfection is not the goal; removing reuse from important accounts is.

For families and teams

Shared vaults beat passwords in a spreadsheet or a group chat. Remove access when someone leaves, and never share a personal master password.