Install a Wireguard VPN server at your home base. Schedule your onsite box to start the VPN connection every hour.
Onsite box is an Intel NUC or similar. I5 Gen 5 or newer will run VmWare. 16gb ram to run 2 virtual machines simultaneously. Tall NUC is nice as it can run both an M.2 and Sata SSD.
A stubby flash drive that can be left with the client.
Prepare a Logitech Unifying dongle for sniffing & injection