According to that guide I read I edited this one:

/usr/lib/ssl/openssl.cnf


but I notice there are others:

/etc/ssl/openssl.cnf
/snap/core20/1587/etc/ssl/openssl.cnf
/snap/core20/1587/usr/lib/ssl/openssl.cnf
/snap/core20/2318/etc/ssl/openssl.cnf
/snap/core20/2318/usr/lib/ssl/openssl.cnf
/usr/lib/shim/mok/openssl.cnf
/usr/lib/ssl/openssl.cnf
/usr/share/doc/nodejs/openssl.cnf.gz
/usr/share/doc/openvpn/examples/sample-keys/openssl.cnf

I am not ot sure which one should be?