Screen saver freezes mac + very high CPU usage

I'm having a similar experience with two newer MacBook Airs on 10.14.6. None of the screensavers involving photos work, regardless if they're my own or the ones Apple provides. System will completely freeze up for almost half a minute (even the clock's seconds freeze up). If I preview it, it's a black screen and takes several seconds to snap back after cancelling. I experience the same issue during Safe Boot, from separate user accounts and after trashing all Screensaver plists.

I believe the issue started yesterday after installing Security Update 2020-004.

UPDATE: Since the latest update to Safari 14 there seems to be an improvement, but i am not sure if this is randomly btw placebo-effect ;(wondering about what Safari got to do with the screensaver)

Waiting for the screensaver when activates takes about 15 seconds. But still not ok because during this time the computer cannot be used.. The process stalls everything for at least 15 seconds. Happens when just looking for the screen-saver-settings in preferences and when screensaver is activated scheduled or by hot corners.

That was the first thing I checked after applying Security Update 2020-005. No change. Attempting to select the Ken Burns effect screensaver or my preferred folder for a screensaver still freezes my computer for about a minute, and doesn't appear to successfully complete. I was wondering if maybe the screensaver app needed to be authorized within Security & Privacy's Full Disk Access, but I couldn't add it there.

Security Updates 2020-004 & 2020-005 also broke the ability of my MS Office 2019's AutoUpdate app to successfully apply updates to my Office apps.

Keep reporting it. Over and over. Not everyone appears to be having this issue so we cannot sit back and wait for someone else to act.

Use this link and be sure to explain that this started with the 2020-004 update:

https://www.apple.com/feedback/macos.html

same here see also thread

https://discussions.apple.com/thread/251589096

seems to work with flury , landscapes- themes have the describeds issue

Well improvement not really essential; still i have to be very patient untill my mac gets responsive when Sierra screensaver is activated.