Thank you for reaching out! I can confirm this and I am sorry aboyt the issue you are experiencing. You can enable this option in General Settings>Network Performance & Security powered by Cloudflare section This will be fixed in the next release.
1. It seems that what can be configured on the admin screen on the cloudflare side can also be configured on the w3totalcache cloudflare config screen, do I have to unify both? Or do w3totalcache’s cloudflare settings take precedence?
2. If I turn on the cloudflare extension, will it work even if I don’t need to check CDN:Enable in w3totalcache’s general setting?
This is the reason why we have the extension. So yes, you can also enable and disable the options in the Clouflare dashboard and W3TC
If you are using the extension you do not need to enable the CDN, as this is differnet type of configuration with other peorviders. This is why Cloudflare has the extension in the W3TC