Install Kalarm, drags in many Akonadi packages, but fails to start and says Akonadi is required?

Freshly installed Kubuntu 19.10

I install Kalarm, which drags in 39 other packages, most with "akonadi" or "pim" in their name.

I then try to start Kalarm, and get a panel saying that "The Akonadi personal information management service is not running. This application cannot be used without it.". Just below is a big "Start" button but clicking on it does nothing.

If I start kalarm in a terminal I see:

org.kde.pim.kidentitymanagement: IdentityManager: There was no default identity. Marking first one as default.
org.kde.pim.kalarm: Preferences::setNoAutoStart: Error writing autostart file: "/home/me/.config/autostart/kalarm.autostart.desktop"
org.kde.pim.akonadicore: Unable to execute akonadi_control, falling back to D-Bus auto-launch

Clicking on the Start button adds another:

org.kde.pim.akonadicore: Unable to execute akonadi_control, falling back to D-Bus auto-launch

Creating the /home/me/.config/autostart/kalarm.autostart.desktop removes the 2nd line but doesn't solve the problem.

Any ideas?

Versions:

plasmashell 5.16.5
Qt: 5.12.4
KDE Frameworks: 5.62.0
kf5-config: 1.0

Edit: So installed mariadb and akonadi server (5.11.3). Rebooted. Now starting kalarm says:

 org.kde.pim.kidentitymanagement: IdentityManager: There was no default identity. Marking first one as default.
Failed to register /MainApplication on DBus
""

akonadiselftest reports two errors:

• MySQL Server default configuration not found
• No resource agents found

Current installation status:

Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name                              Version            Architecture Description
+++-=================================-==================-============-==========================================
ii  akonadi-backend-mysql             4:19.04.3-0ubuntu3 all          MySQL storage backend for Akonadi
un  akonadi-backend-postgresql        <none>             <none>       (no description available)
un  akonadi-backend-sqlite            <none>             <none>       (no description available)
ii  akonadi-server                    4:19.04.3-0ubuntu3 amd64        Akonadi PIM storage service
un  akonadiconsole                    <none>             <none>       (no description available)
un  libakonadi-kf5                    <none>             <none>       (no description available)
ii  libkf5akonadicontact-data         4:19.04.3-0ubuntu1 all          akonadi-contacts - data files
un  libkf5akonadicontact5             <none>             <none>       (no description available)
ii  libkf5akonadicontact5abi1:amd64   4:19.04.3-0ubuntu1 amd64        Akonadi contacts access library
ii  libkf5akonadicore-bin             4:19.04.3-0ubuntu3 amd64        Tools for Akonadi core library
un  libkf5akonadicore5                <none>             <none>       (no description available)
ii  libkf5akonadicore5abi1:amd64      4:19.04.3-0ubuntu3 amd64        Akonadi core library
ii  libkf5akonadimime-data            4:19.04.3-0ubuntu1 all          akonadi-mime - data files
ii  libkf5akonadimime5:amd64          4:19.04.3-0ubuntu1 amd64        Akonadi MIME handling library
ii  libkf5akonadiprivate5abi2:amd64   4:19.04.3-0ubuntu3 amd64        libraries for the Akonadi PIM storage serv
ii  libkf5akonadisearchpim5:amd64     4:19.04.3-0ubuntu1 amd64        Akonadi search library
un  libkf5akonadisocialutils5         <none>             <none>       (no description available)
ii  libkf5akonadiwidgets5abi1:amd64   4:19.04.3-0ubuntu3 amd64        Akonadi widgets library
un  libkf5akonadixml5                 <none>             <none>       (no description available)
ii  libkf5libkdepimakonadi5:amd64     4:19.04.3-0ubuntu1 amd64        KDE PIM Akonadi library
ii  libkf5mailtransportakonadi5:amd64 19.04.3-0ubuntu1   amd64        mail transport service library for akonadi