I think you got it wrong.
First, the Jamie Dimon attack in 2017 was done not to attack bitcoin per se, but to cause panic, I mean he wanted to bring the price down because they're secretly buying tons of bitcoin during the dip.
https://news.bitcoin.com/after-the-boss-calls-bitcoin-a-fraud-jp-morgan-buys-the-dip/And then they launches their own tokens, we can't call it crypto though because its for their private used and I'm sure they won't offer it to investors. Instead they will used it around their banks to help lessens the fees and the transaction time for their clients.
Definitely a buying strategy. Old guys here were witnessed about this, after saying bitcoin is fraud, the price dump and he saw this as a best entry point.
JP Morgan was nothing but a clever guy that uses his connection thus abuse his power.
We can anticipate that his shit coin will build by hype, oh I won't be surprise then.