I have the AAWireless dongle for my car and one of the advanced options is to "remove tap restriction" to allow over 6 taps in succession. Bonus, you can convert wired AA to wireless AA.
RustyHeater
if you get/have AAWireless dongle you can set it to only connect when it also connects to the radio Bluetooth.
If not You can get a toggle switch USB cable to make disconnecting easier.
Have not tried, but Sonoff has a usb switch that you can control remotely and could potentially use Google Home. https://sonoff.tech/product/diy-smart-switches/micro/
Microsoft's Wolverine for the TCP stack was not available until Windows 3.11. An argument could be made that these systems are defacto air-gapped as they cannot communicate with modern networking.
The good news is anyone can grab the GrapheneOS PDF viewer. https://github.com/GrapheneOS/PdfViewer Or from the Google Play store https://play.google.com/store/apps/details?id=app.grapheneos.pdfviewer.play
J1900 has no hardware switch. Every packet goes through CPU, so even LAN to LAN uses processing power. Add pfsense to the mix and it's probably choking.
CS integrates with RD if you use the Streamio extension. You setup RD in Streamio first and then copy over the API url into CS.
Not 6E but the GLINet Flint 2 runs a flavour of OpenWrt 23.05.
I own the original Flint and I have been really happy with it. It's has a "fisher price" mode for most people; but then you can also log into Luci and really tinker under the hood.
You need something in between to intercept the data and it just so happens that AAWireless works for that too while it's acting as a wireless bridge.