Process to get rid of LuCI HTTPS certificate warnings not working

I followed it to the T, but the "Not secure" thing in Chrome is still there.

opkg update && opkg install openssl-util luci-app-uhttpd - Done
Create /etc/ssl/myconfig.conf with the following content: Done.

DNS.1 =
IP.1 =

Step 6, 7, 8, 9, 10 Done. Imported mycert.key to Trusted Root Certification Authorities store in Chrome, and restarted browser. "Not secure' msg still there. Urg. Will redo.

If you read the certificate details, are they updated or the browser still has cached the old one?

You don't export the key to your PC (or anywhere); you need to tell the browser to trust the public part of your certificate.

That is done on the PC side by following the instructions in the "chain of trust" section.