the "10 ANT" pad is not very close to the ANT hole, are you sure it is not affecting the antenna length?

Ok, keep us posted. Also make sure about trace length for the antenna as I remember there should be some specs about it.

In arduino IDE, boards manager

What boards definitions are you using for arduino?

I usually enable wdt at beginning of loop and disable it before sleep

If you can program it yourself, it could work but you need to figure out where the rs485 is connect to the arduino to be sure

If you don't need specific features in 2.3, then stick to 2.2 that works well.

I'm talking about normal rfm69w, the rfm69hw are the high power ones but the footprint is the same

do you think you could fit the RFM69W modules?

Nice. You may consider adding a small connector for external antenna