Yes, technically. This message is saying no new firmware updates will be forthcoming for your model. The unfortunate reality, though, is that most consumers rarely update their router firmware, regardless.

There has been a very large increase in attacks on home and small business routers, which are then used for botnets and espionage. Look for articles on Small Office/Home Office (SOHO) router attacks, but here are a few:

https://www.bleepingcomputer.com/news/security/cisa-vendors-must-secure-soho-routers-against-volt-typhoon-attacks/

https://arstechnica.com/security/2024/02/kremlin-backed-hackers-are-infecting-ubiquity-edgerouters-fbi-warns/

https://thehackernews.com/2024/05/mysterious-cyber-attack-takes-down.html

https://www.malwarebytes.com/blog/news/2024/02/fbi-removes-malware-from-hundreds-of-routers-across-the-us

https://www.cisa.gov/news-events/cybersecurity-advisories/aa25-239a

https://www.cisa.gov/sites/default/files/2024-01/SbD-Alert-Security-Design-Improvements-for-SOHO-Device-Manufacturers.pdf

SOHO routers are ubiquitous and inexpensive devices that connect millions of Americans and small businesses to the internet. However, due to widespread sale, and subsequent use, of insecure SOHO routers that lack basic security features, threat actors, including the PRC-sponsored Volt Typhoon group, are exploiting these devices at scale.

If you are concerned, it may be worth investigating if your device supports OpenWRT, or upgrading to a newer router under active maintenance. I see the Netgear R6700 as supported on the OpenWRT Table of Hardware.