Verified with one additional of  "overlay_vaapi" so I have a modified patch for cinelerra-5.1/ffmpeg/plugin.opts to include that.  I think we have for sure determined by now that without significant/major changes any plugin that shows up as "Input/output error" or "Operation not permitted" will never work.  Those with error of "Invalid argument" have some possibility IF a starting correct argument is supplied in this file, but for these 2 new ones, that seems impossible.

Andrea, since you successfully compiled ffmpeg 5.1, and ONLY IF YOU HAVE THE TIME, could you test the following just to make sure that they do not crash the system?

blockdetect
blurdetect
chromakey_cuda
colorchart
colorspectrum
grayworld
hsvhold
hsvkey
latency
pizelize
scharr
siti

adecorrelate
adynamicequaalizer
adynamicsmooth
afwtdn
alatency
apsyclip
aspectralstats
atilt
dialoguenhance
tiltshelf
virtualbass

And then if you still have more free time, could you update the file cinelerra-5.1/info/plugins.txt to include a very short one line of information that shows up in the Resources window when you have "Info on" turned on?  This file is very picky about formatting though.