Well done Stef. Interesting conversation you were having with yourself there 
The reason you cannot send more than 20 characters is that the BLE data packet size defaults to approx 32 bytes, including it's own header & footer. So yes, a good way to work with that is to send your text via several packets. You can, depending on the receiving device, increase the MTU (Maximum Transmission Unit), up to a maximum of 247 bytes (Both devices must support BLE v4.2 - v5.0).
You can find the Blocks to make that happen in the BLE Extension:
