Nextcloud docker + Onlyoffice docker - access from internet

My server: Ubuntu server 22.04
Hardware settings: 8 CPU + 10 GB RAM

Greeting,
I have installed Nextcloud + Onlyoffice dockerized based on this tutorial.

and text tutorial Roll Your Own Google Docs with NextCloud and OnlyOffice in Docker

Everything is working well on localhostā€¦
But I would like to have it accessible from outside of LANā€¦ I mean from the internet.

So I am looking for a solution how to solve it via NGINX proxy.
I succeed to connect nextcloud.mydomain.com via NGINX to mynextcloudlocalip.8080 but I do not know how to set up Onlyoffice app settings for myonlyofficelocal:8081

I tried to link Onlyoffice docker through NGINX similar way as Nextcloud docker but it does not work.

I also tried to forward port 8081 to myonlyofficelocal:8081 on my router and set mypublicip:8081 in Onlyoffice app settings.
It does not work either.
No idea how to set it up.
Can you please somebody help me set it up to work?
Thank you.