Hey, there. I'm running a Raspibolt node.
Tor is very rarely the problem with slow syncing. It's either failing to find peers, or there is lack of memory. But before that, is your external drive an HDD? If that's so, then expect slow syncing. When I finished syncing a couple of years ago, I think it had taken me around 2 weeks, because of that. So, maybe you should shut down everything, move your blocks and chainstate in an SSD, let it sync there, and then move these directories back to your HDD drive.
In addition, the HDD can contain a symbolic link that'll be pointing at the location where the blocks and chainstate are stored in an SSD, and the system will run on the link as though it's the main directory. Symbolic link can be created with Mklink command using command prompt, and it's preferable to run it as admin. This link would be helpful
https://www.howtogeek.com/16226/complete-guide-to-symbolic-links-symlinks-on-windows-or-linux/Also a thread where such a problem was discussed and solved
https://bitcointalk.org/index.php?topic=5387672.0