I found this unofficial build on XDA https://forum.xda-developers.com/t/rom-vendor-oneui3-1-s20-port-treeui-0-9-5-beta-for-a8-a8-a7-m20-m30.4264871/
Yes.that was my mistake and Samsung fooled us providing only one major update. Well i am going to buy new phone soon and this time not a Samsung device.
