Sounds like you are forwarding VNC data directly to your pi. A strong password isn't enough. A brute force attack could potentially break your password. More importantly, if you are communicating over an insecure connection someone could sniff out your password pretty easily. I highly recommend you remove the port forwarding you set up.
I tried to get info on your router but there doesn't seem to be much...my guess is that is doesn't support configuring a vpn anyway. At this point I can only think of a few options.
Get a router that has built in vpn capabilities (newer Asus and Netgear routers tend have these).
Use you rPi as your Vpn server. The video below was a huge help to me when I had this setup (before I bought my new router).
No problem. Here's the link to where you can create a free RealVnc Connect account. I would go ahead and set this up until you choose how you want to proceed....or maybe stick with this permanently if the vpn option turns out to be too painful to configure.
Wow...that's exactly what I'm researching as we speak. I setup pihole last week and I'm trying to figure out how to setup a secondary pihole server in docker. About to give up though. I'm new to Docker and it seems to need a bit of an advanced config.
