Also, re your 20-odd miles, my understanding of north east geography having lived there for years is that Middlesbrough feels like a world away. No-one from Newcastle, Sunderland, Tyneside or Wearside has any real reason to go there and there are no amazing transport connections. What there is is a Tyne -Wear urban area in which fans of both clubs socialise and work. Middlesbrough feels as distant as Leeds in that respect. There are probably more Manchester United and Liverpool fans in Tyne and Wear than Middlesbrough fans. There’s just no roots for a rivalry.
It’s hyped up because they have a radgie element of fans and are desperate for a derby. That doesn’t make it a derby. The Sunderland Middlesbrough matches I’ve been to have been pretty tame, like another game. Newcastle versus Sunderland is about 100 levels above. I bet most Mag fans would say the same
The levels of passion and hatred at Sunderland v Newcastle games is way above Middlesbrough Sunderland (or Newcastle). Newcastle Sunderland is a bona fide proper derby in every sense of the word. It’s absolutely vitriolic and raw and takes up the week before and after (plus bragging rights), with fans working and socialising with each other in local areas.
Middlesbrough has none of that.