Thank you for bringing this to our attention.
After investigating the issue, I found that while the media/com_sppagebuilder/assets/iconfont folder and its files had been removed, the corresponding records were still present in the database. As a result, SP Page Builder continued attempting to load those non-existent CSS files, which caused the repeated 404 requests and negatively impacted the site's loading performance.
I have now removed the obsolete database records, so the site will no longer attempt to load those missing icon font files. This should resolve the 404 errors and improve the site's loading speed.