Why is Bitcoin Core full node so slow to sync?
First of all you need to tail your $BITCOIN_DATADIR/debug.log and search for clues. You might solve your problem by just looking at the messages there. Here's a sample:

2019-10-13T18:17:11Z socket recv error Connection reset by peer (104)
2019-10-13T18:24:48Z socket recv error Connection reset by peer (104)
2019-10-13T18:28:17Z socket recv error Connection reset by peer (104)
2019-10-13T18:29:10Z socket recv error Connection reset by peer (104)


In my case I had several peers drop their connection but the syncing soon restarted with fresh peers.

The blocks you're stuck on are from August 2017, right after the Bitcoin Cash fork. Are you running the most recent version of Bitcoin Core? Have you tried clearing the blockchain altogether and restarting sync from zero? (Note: do not delete your wallet.dat file, just the files under blocks/ subdirectory.)

Is there other software running that could be connecting to peers' port 8333? Peers might be banning your IP for some reason. Is this PC clear of malware that could be scanning for port 8333 of network peers? This could cause your IP to be blacklisted.

Finally, have you tried forcing a IP address change? If this is network-related then rebooting your gateway to force a new IP could solve the problem.