Certificate Issue fixed. Turns out, when my site had been working previously, it was never using Cloudflare's certs as intended, instead falling back to Caddy's default TLS behavior. I've restored this functionality and will be looking for an opportunity in the future to properly utilize Cloudflare certs.

Drag and dropped all site and caddy configuration from PI 400 to PI 5, cloudflare is rejecting visits with a 525 error.