> you missed  -lSvtAv1Enc for libs ....

Sorry, I didn't tell you that pkg-config can't find anything about svtav1:

$ pkg-config --libs lSvtAv1Enc
Package lSvtAv1Enc was not found in the pkg-config search path.

Perhaps you should add the directory containing `lSvtAv1Enc.pc'
to the PKG_CONFIG_PATH environment variable
Package 'lSvtAv1Enc', required by 'virtual:world', not found

Same error as my first attempt with the wrong script.

> mmm.. try speed test again? :).

Yes, I did the speed test and it matches sometimes libaom 3.6,
sometimes 3.8; never 3.4 :)

Now it's bedtime for me too...