Time sensitive networking [TSN] on NX

on client with eth0 &openvpn tun0;
one ptp4l synchronizes eth0 with server.

ptp4l[899465.839]: master offset       -177 s2 freq    +998 path delay      3674
ptp4l[899466.939]: master offset       -241 s2 freq    +880 path delay      3674
ptp4l[899468.039]: master offset        -81 s2 freq    +968 path delay      3674
ptp4l[899469.139]: master offset       -354 s2 freq    +671 path delay      3903
ptp4l[899470.239]: master offset      -1065 s2 freq    -146 path delay      3903

on the tun0 interface I run:

ptp4l -i tun0 -m -S
ptp4l[899349.695]: port 1: INITIALIZING to LISTENING on INIT_COMPLETE
ptp4l[899349.695]: port 0: INITIALIZING to LISTENING on INIT_COMPLETE
ptp4l[899356.936]: port 1: LISTENING to MASTER on ANNOUNCE_RECEIPT_TIMEOUT_EXPIRES
ptp4l[899356.936]: selected local clock 000000.fffe.000000 as best master
ptp4l[899356.936]: port 1: assuming the grand master role

on a remote(local) computer connected through the internet [openvpn] I also run:

sudo ptp4l -i tun0  -m -s -S
ptp4l[51276.940]: port 1: INITIALIZING to LISTENING on INIT_COMPLETE
ptp4l[51276.940]: port 0: INITIALIZING to LISTENING on INIT_COMPLETE
ptp4l[51283.543]: selected local clock 000000.fffe.000000 as best master
ptp4l[51289.885]: selected local clock 000000.fffe.000000 as best master
ptp4l[51297.223]: selected local clock 000000.fffe.000000 as best master
ptp4l[51303.369]: selected local clock 000000.fffe.000000 as best master

it won’t work over the internet[vpn] with software synchronization? ntp should be used instead? or still could work? with adjusted parameters?