When upgrading from iPhone 6 to iPhone 11, do you transfer data first then activate or vice versa

Viceversa.

See also this support guide:--> Transfer data from your previous iOS device to your new iPhone, iPad, or iPod touch - Apple Support

Regards

Giulio

Simplest way:

1. Make a backup of your iPhone 6 locally using computer iTunes.
2. Activate your new iPhone than restore from the iPhone 6 backup.

Note: Apps are not part of a backup, but it will automatically re-download on the new device

after the restore (make sure iPhone is connected to the Internet when you restore from backup).

When upgrading from iPhone 6 to iPhone 11, do you transfer data first then activate or vice versa

You won't be able to transfer data until the new phone has been activated. Not a choice.

I like iPhone 6

iPhone