Since you're not seeing Banking as an option in your left navigation bar, I'd recommend checking to see if the account was switched to Business view.
When using Business view, you won't see a Banking option displayed in your left menu. Instead, you'll have to go to Bookkeeping to access the Banking screen.
To confirm which view you're currently using, use your Gear (⚙️) icon, then check if the account says Switch to Accountant view or Switch to Business view.
If it says Switch to Accountant view, you're currently in Business view. You can select Switch to Accountant view to see your Banking option listed in the left navigation bar again.