I have nextjs + payload (+ disc) + mongodb (+disc) configuration

I want to have local backup of this. How can I do that?

The service the volume is attached to would have to provide a way to give you the contents of the volume or the just the relevent data, for mongo this is done with the CLI tool mongodump, for payload you would likely have to connect it's volume to a filebrowser service to download the files.

Can I suspend my env for a month ? How can I export that copy to remove env and for example recover it in 6m ?

Just remove the active deployments, then redeploy when you want your services back online.

mongo - ok

but cms - any simple way to connect storage to any file browser?

https://railway.app/template/Nan7Bs - Please carefully read the overview.

perfect, thank you so much