SOHO Device Exploitation
Among the very many to be found on the Internet, here is one interesting write-up of the discovery and exploitation process of a SOHO device (a Netgear router).
Another interesting study on router security was performed by the Fraunhofer Institute in 2020, finding a surprising number of vulnerabilities.
Here is yet another mass router study, by The American Consumer Institute in 2018, which also discovered a remarkably large set of vulnerabilities.