2N2222 low side relay switch not turning off
So before pressing the button voltage measures 6.9V. Press the button and voltage difference drops to 0.25V. Release the button and voltage goes up to 6.5V – Bananaman 20 mins ago

Given that your supply is 12V it should measure near 12V or near 0V between collector and emitter. The 0.25V is good, but the 6.9V and 6.5V are not.
Either your 2N2222 is connected backwards or it is defective,
check that it is oriented correctly and/or replace it with a new one.
From the photo it looks like you have the transistor backwards
this may have damaged it.