There exists an active GitHub site with a zstd-v1.5.7-win64.zip downloadable file
Yep - that should do the trick.
Copy its dll/libzstd.dll.a into the ext/zstd/lib folder, and rename it to libzstd.a.
Then copy the dll/libzstd.dll file into your strawberry/perl/bin folder.
Then just do step "5." from my earlier post.
Worked for me !!