QUANTUMINSERT (QI) is actually a relatively old technique. In order to exploit it, you will need a monitoring capabilities to leak information of observed TCP sessions and a host that can send spoofed packets. Your spoofed packet also needs to arrive faster than the original packet to be able to be successful.
Any nation state could perform QUANTUM attacks as long as the traffic passes through their country or possesses other capabilities to get the required TCP session data.
QUANTUMINSERT could be used for lateral movement within internal networks.
Detection is possible by looking for duplicate TCP packets but with different payload and other anomalies in TCP streams.
The usage of HTTPS in combination with HSTS can reduce the effectiveness of QI. Also using a content delivery network (CDN) that offers low latency can make it very difficult for the QI packet to win the race with the real server.