In its essence, FlexVPN is the same as DMVPN. Connections between devices are still point-to-point GRE tunnels, spoke-to-spoke connectivity is still achieved with NHRP redirect message, IOS routers even run the same NHRP code for both DMVPN and FlexVPN, which also means that both are Cisco's proprietary technologies.

DTLS is used for delay sensitive applications (voice and video) as its UDP based while TLS is TCP based.
Therefore DTLS offers strongest throughput performance. The throughput of DTLS at the time of AnyConnect connection can be expected to have processing performance close to VPN throughput.

The Cisco Umbrella Multi-Org console has the ability to upload, store, and archive traffic activity logs from your organizations' Umbrella dashboards to the cloud through Amazon S3. CSV formatted Umbrella logs are compressed (gzip) and uploaded every ten minutes so that there's a minimum of delay between traffic from the organization's Umbrella dashboard being logged and then being available to download from an S3 bucket.
By having your organizations' logs uploaded to an S3 bucket, you can then download logs automatically to keep in perpetuity in backup storage.