Mmmm. That Sandwalker enemy can only be blocked by operators with 4 blocks...
Looking through GamePress, some operators that can achieve that:
With Skills:
Nian S2 & S3 (S3 can give +1 Block to nearby operators)
Gavial Alter S3
Vulcan S1
Cuora S2
Ling S3 with her combined summons
With Modules:
Hoshiguma, Heavyrain, Croissant and Matterhorn. Nian also has a module that lets her block 4 enemies, but I'm not sure if it's available in global yet.
There could be more operators, but I mostly just checked the defenders lol