OpenVPN Quality/Security of OpenVPN and Config/Certs in 2022

I apologize that I am so poor at searching through prior posts that I have to ask this.  I simply can't find definitive answers.  There are a number of posts regarding the Netgear Openvpn that is built in to many of their routers.  Across time there have been security concerns about the config files and the certificates that the implementation uses.  

Can someone provide some detail on the "current" implementation (circa 2022; I guess using the latest official firmware update):

1. What is the quality of the certificates?

2. Do all Netgear routers use the same certificates?  If someone has those and my IP address can they connect to my VPN?

3. Is there a way to force an update to the certificates, for instance if one wants to deny service to someone who has the current certificates?

If you have answers or can point me to a good, current post that already covers those, I would greatly appreciate the help.  I have listed my model but I think the question is generic to a number of Netgear models that run OpenVPN.