Solved Basic SRM Ipv6 config

[Namaste]

Hi all,
I am struggling with basic IPv6 config on my MR2200. I don't know a lot about this and have made some research on the web, but the info I found concerns advanced problems only and didn't help me. Synology's User Manual doesn't help either. So, maybe someone here can help by answering some questions or referring to useful resources?

• First a few words about the context : My ISP provides expensive fix IPv4 addresses, but also free v6 ones. This is why I am going with it.
• So my ISP provided me with an IPV6 prefix under the following format : xxxx:xxxx:xxxx::/48, as well as two different Dns-Server addresses.
• They added the following comment : "The IPv6 prefix will be assigned via DHCPv6 prefix delegation. With that /48 network, you can now assign fix /64 network adresses on the LAN interface of your router. If you would like reverse DNS delegation, please provide us with at least one server of names". (I guess there is a translation mistake here. It's a German speaking company that wrote me in French, and I am trying to report it here in an approximately understandable English .... Do they mean "at least one server name"?)
• my goal is simply to be able to contact my DSM with a fix public address, instead of using QuickConnect or DDNS services.

Now my questions :

• I understand the first three groups of Xs in the address I received are the so called "prefix". In other words, this is the address now pointing to my home. The rest of the address (empty in the above example) is dedicated to the LAN side. Is that correct?
• consequently, every device I have on the LAN side could actually get its own fix public address in the form of "my:prefix:address::device:A", as long as I configure IPv6 on the LAN side as well. Is that correct? (No plan to do this, just asking for my understanding)
• SRM's GUI has many options concerning IPv6 setup (e.g. "type: 6in4, 6to4, manual, etc." ) . I couldn't find a tutorial or documentation that help me understand what it all means, and what I should do with all of this. Are there some "standard settings" you know I should use? Do you know some resources I could use to help do the right choice? or will my ISP actually be the only one to know?
• How will I call home on a specific port with an IPv6 address? I am wondering because of the address format, which is using ":" already...
• How can I check if my config is correct? Should a site like "whatsmyipaddress.com" or "ipv6-test.com" show ipv6 addresses, or could it be that my setting is OK, but they only show my IPv4 address? I am asking this because I've been visiting these sites after trying different settings, but I only got IPv4 indications.. .
• how do you understand the comment my ISP provided with regard to delegation? Should I do something with that?

I hope my questions/ideas are clear enough so someone can help. Thank's for your help.