No, iOS 14 Widgets do not drain the battery. All they do is display something that is already on your phone or available on the web.

Does iOS 14 ruin your battery?

iOS 14 has introduced many new features and changes for iPhone users. However, whenever a major update to an operating system drops, there are bound to be issues and bugs. … However, the poor battery life on iOS 14 can spoil the experience of using the OS for many iPhone users.

Does iOS 14.4 fix battery drain?

iOS 14.4 battery drains

At the moment, there’s no precise solution to the battery drain issue, so if your iPhone loses its juice faster upon installing the new update, you will probably have to wait for Apple to tackle it in future releases.