Correct organization of the backup channel on the server, how?

Question

Server equipment

Hello! I really need advice on organizing uninterrupted access to the servers of a small office.
I’ll warn you right away that I’m not a pro in networks and servers, but I have some knowledge.
There is a server that is now connected directly to the Internet, it runs 1C, VPN, video surveillance and much more. Clients get access to it only via the Internet (25 remote clients) on average 670 gigabytes of traffic per day.
Due to the growth of the company and to increase availability (tired of provider failures), it was decided to separate the servers to different pieces of iron + connect 1 more Internet channel.
As I understand it, the problem with 2 Internet channels can be solved with a router with 2 WAN ports by forwarding ports to different physical servers for both connections. If communication is lost on 1 line, everyone will simply change the ip address in the vpn connection and everything will work.
But this method seems to me not very beautiful, since on each computer network drives will also be duplicated, and 1C will behave like hell.
Can anyone offer a better solution to the problem?

Answer 1

Install a separate server under 1C, transfer all work with it to terminal mode via RDP. The traffic will drop sharply, the speed of work will increase, if the connection is broken, the working session will remain on the server. There may be problems with forwarding printers and / or cash equipment.
For VPN, you can use both hardware (Mikrotik, Cisco ASA) and software (OpenVPN, WinServer VPN, SoftEther) solutions. When properly configured, the client will use the same address for the RDP server after connecting, regardless of the channel.

Answer 2

Maybe someone has experience using 2wan on zyxel giga3?