It depends on why you use them. I use BunnyCDN which is fine for my usage. I use my own video transcoding servers (hosted on Netcup for suuuper cheap). I use Render for my applications. I use Cloudflare for a proxy, but could probably replace it in a week or so using Go + Caddy + a VPS of some kind and it would probably be fine for my use case.
It really depends on your use case and volume.