So I had an existing data/conf/nginx/redirect.conf from version < 2025-01 and after setting HTTP_REDIRECT=y in mailcow.conf and recreating the nginx container per the docs the nginx container entered a looping restarting cycle.
Error being thrown by the container was:
nginx-mailcow-1 | Render config
nginx-mailcow-1 | 2025/02/05 09:47:40 [emerg] 1#1: a duplicate default server for 0.0.0.0:80 in /etc/nginx/conf.d/redirect.conf:3
nginx-mailcow-1 | nginx: [emerg] a duplicate default server for 0.0.0.0:80 in /etc/nginx/conf.d/redirect.conf:3
Renaming the pre-existing redirect.conf file solved the problem:
cd /opt/mailcow-dockerized
mv data/conf/nginx/redirect.conf data/conf/nginx/redirect.conf.pre2025-01a