I find almost zero reference to AC86U router. Most of the into I find say 86U but mean 68U. Is this AC86U a European model perhaps?
If you have the ability to configure OpenVPN on the AC86U router, then follow the directions on this site. You will need to download the configuration files from PIA related to OpenVPN. In the configuration files are certificates you will need.
The DSL is a modem/router not a straight router so the link does not apply. You cannot put ASUSWRT onto DSL devices.
This has nothing to do with the issue. A modem cannot route unless it has a router connected to it either in the same box or separately. A router cannot modulate a signal unless it has a modulator physically connected to it. These are two totally different functions. Therefore the link applies to the router portion of the box if the box's firmware supported VPN.
What does not apply is the fact your AC86U may not have the required firmware to support VPN operations. If that is the case then you will not be able to do what you wanted. But the fact that the AC86U is a modem/router is moot.
So you found the tab, on your own, with a little research. Hope you can get it working.
Comments
If you have the ability to configure OpenVPN on the AC86U router, then follow the directions on this site. You will need to download the configuration files from PIA related to OpenVPN. In the configuration files are certificates you will need.
The DSL is a modem/router not a straight router so the link does not apply. You cannot put ASUSWRT onto DSL devices.
1. Follow these instructions from OpenVPN Setup tab;
https://support.hidemyass.com/hc/en-us/articles/204449557-Asus-VPN-Client-Setup-Original-firmware-
2. Download the .OPVN file server file of you choice (eg; Sydney, Toronto etc) and the certificate CA file from here;
https://helpdesk.privateinternetaccess.com/hc/en-us/articles/218984968-What-is-the-difference-between-the-OpenVPN-config-files-on-your-website-
I used the top one which is the DEFAULT and the one recommended. The files are in a ZIP file
What does not apply is the fact your AC86U may not have the required firmware to support VPN operations. If that is the case then you will not be able to do what you wanted. But the fact that the AC86U is a modem/router is moot.
So you found the tab, on your own, with a little research. Hope you can get it working.