Issue: I added the font file to the Assets folder, updated the code, checked the devtools and it was showing a network status code of 200. The item told me it was displaying the correct font, but the font visibly remained a default.
Reason: There is an internal Shopify bug that’s been around since at least 2022 that corrupts woff files on load to the assets.
Solution: Add the font to the Files folder and call it from there.
Add to this folder → https://admin.shopify.com/store/*store code*/content/files
Use code like this:
Add just below {{ content_for_header }}
add at the very end of section:
PS. always make sure that you have a backup font file like a woff2. Browsers like it.
references: where i found my solution