The General settings tab no longer exists. As of version 2.1.0 its contents were split across several tabs under Points & Rewards › Settings. This page says where each group of settings went.

Points and rewards labels

Labels, the points value prefix and the points icon are on the Points Label tab. See Rename your points and add a points icon.

Points messages on product and shop pages

These are on the Product Pages tab. See Show points on product and shop pages.

Terms and conditions

The programme terms and their popup are on the Terms and Conditions tab. See Add terms and conditions to the rewards dashboard.

Theme colours, dark mode and dashboard tabs

These were never on the General tab, despite earlier versions of this page saying so. They are in the Theme Colors, Dark Mode and Dashboard Tabs sections of the Rewards Dashboard tab. See Customise the rewards dashboard.

Showing the Rewards tab on My Account

Show Rewards tab on the My Account page is on the Rewards Dashboard tab. See My Account Rewards Dashboard.