Linux Controller behind NAT (SSL Config)

OS Name/Version: Debian 12

Product Name/Version: v2.5.0.4

Problem Description:
Attempting to install an SSL cert obtained through certbot as a PEM at first, then attempted to package it as a pfx using openssl. The constraints are that this isn’t open to the web and uses DNS Authentication with Letsencrypt

The system refuses to accept either format of the cert attempting to modify the AMPConfig.conf

Actions taken to resolve so far:

I’ve been attempting step 4.1 with both formats using a combination of cert or fullchain with no luck.
Unable to install SSL cert on Ubuntu ADS Controller (my error)
Reading this, it indicates that the PFX route isn’t an option on Linux despite what step 4.1 states.

Is there any other way? As I stated, I don’t have 80 or 443 open and use a DNS auth for LE to produce the cert. I’ve checked the cert integrity in all cases and it’s fine, the issue is in applying the cert to AMP.

Use the certificate with a local nginx reverse proxy rather than with AMP itself directly.

Done and that works, but I’m unable to add new instances now. I’ve attempted ampinstmgr repairauth using the new path and I can log into amp with SSL enabled, but the non SSL route of 8080 is still accessible, and neither works for adding new instances to the controller.
The message is that the supplied login details were rejected by the controller.