yes and NO
its a combination a two standard tools in linux, mdadm and lvm2 (and the file systems ability to "grow")
any linux should be able to read a SHR volume, the special of synology is automatically creating and extending things without the user having any trouble or even seeing how its working (but it needs some basic understanding of the matter - your example with 3 x 8TB and adding a fourth disk in a 4 disk units will not work as the added bigger disk part over 8TB will not have redundancy and would not be used in a SHR, only if one the three 8TB disks is also replaced with a