With TLS 1.3 more parts of the handshake got encrypted (e.g. the certificate), but sometimes it's still helpful to look at the complete handshake.

curl uses the somewhat standardized env variable for the key log file called SSLKEYLOGFILE, which is also supported by Firefox and Chrome. wireshark hides the setting in the UI behind Edit -> Preferences -> Protocols -> TLS -> (Pre)-Master-Secret log filename which is uncomfortable to reach. Looking up the config setting in the Advanced settings one can learn that it's called internally tls.keylog_file. Thus we can set it up with:

sudo wireshark -o "tls.keylog_file:/home/sven/curl.keylog"

SSLKEYLOGFILE=/home/sven/curl.keylog curl -v https://www.cloudflare.com/cdn-cgi/trace

Depending on the setup root might be unable to access the wayland session, that can be worked around by letting sudo keep the relevant env variables:

$ cat /etc/sudoers.d/wayland 
Defaults   env_keep += "XDG_RUNTIME_DIR"
Defaults   env_keep += "WAYLAND_DISPLAY"

Or setup wireshark properly and use the wireshark group to be able to dump traffic. Might require a sudo dpkg-reconfigure wireshark-common.

Regarding curl: In some situations it could be desirable to force a specific older TLS version for testing, which requires a minimal and maximal version. E.g. to force TLS 1.2 only:

curl -v --tlsv1.2 --tls-max 1.2 https://www.cloudflare.com/cdn-cgi/trace