I am not sure about your requirements. So I can only provide some general information. Hope it is helpful.
FTP/SFTP hosting service is usually used for transferring large folders/files among companies. Each user usually needs to log in to the FTP server. Such data is not for public access and usually does not need CDN service. FTP has a feature called "Anonymous FTP", which allows anybody to access without login. Data available to anonymous FTP is public. You can use a CDN service if you experience slow downloads.
However, DriveHQ has huge amount of bandwidth. In most parts of the world, you don't need another CDN service if you use our anonymous FTP feature.
In fact, DriveHQ can act as an easy and low-cost CDN alternative. If you use a web/FTP hosting service with limited bandwidth or monthly data limit, you can use our Static Web Hosting / File Hosting / Anonymous FTP service. You can either migrate it to our service, or move some large files (image/video files) to DriveHQ. DriveHQ can offer huge amount of bandwidth and monthly data at much lower cost than the Bigtechs and CDN service providers. Please visit:
https://www.drivehq.com/features/webhosting.aspx
For the anonymous FTP feature, please watch this video:
https://youtu.be/9qCAk1abMiQ