Screensaver in Xubuntu 20.04

[MR ZenWiz]

When I was running 18.04 (and before), I used xscreensaver because it
worked really well.

On 20.04, the GL slideshow disappeared (and I haven't tracked down how
to restore it, though I will today).

I've been using the xfce4-screensaver, and it looked like it would do
the job just fine - until it didn't.

Two major issues:

I have the screensaver set to go idle and save the screen after 145
minutes, which is what I used for xscreensaver.  xfce4-screensaver
nevre lassts that long - usually less than 30 minutes.  Shortly after
the screensaver starts up, the slideshow goes away.

I thought I could fix that last part by adding the power manager
(which xscreensaver never needed) and it now never shuts off the
display.

The other issue is that I have my crontab file set to run xflock4
every hour during the day - so I don't spend that much time
uninterrupted in front of the computer.  Again, this worked fine under
18.04.  Now it doesn't work at all.  There is no correlation I can see
between when the creen locks and the time, except that it locks up
after about 30 minutes of inactivity, in spite of the above settings.

Is there a rationale for this (and what), or should I go back to
xscreensaver (seems likely)?

Thanks.

Mark Richter, Senior MoTS
http://www.linkedin.com/in/markrichter1
Registered Linux User #472807 http://counter.li.org/
FSF Member #12694 http://www.fsf.org