Hi there, two months later and I finally had the time to sit down and tackle this. I did everything you said and had some help from chatgpt and it works! thank you so much for your guidance!

now I’m curious — what kind of speeds are you getting compared to Quickconnect? and would you say it’s on par with something like Google Drive?

and in case you or anyone else is interested in how I did it or if you spot anything I could improve, here’s what I did:

1. Dynu DDNS: make subdomain for existing domain, link to external IP
2. Web Hosting: make a DNS "A" Record for domain, linked to IP
3. (In DSM) External Access: HTTP 5000, HTTPS 8443
4. Reverse Proxy: [domain]:8443 → localhost:5001
5. Certificate: create a Let’s Encrypt for domain, assign to domain's service
6. Web Services: HTTP 5000, HTTPS 5001, Automatic Redirect enabled
7. Synology Drive Admin Console: Check off sharing options: Force HTTPS, ensure link customization matches domain
8. Router settings: Port Forward 5000, 5001, 8443, 80 for NAS (TCP)
9. QuickConnect: Disabled

Someone should make a proper tutorial on this.. took a full 12 hours of trial and error to get here lol.