What type of VPN to choose and what equipment for it?

Question

VPN

Hello.
There is an organization with a central office of 10-15 people. Employees sometimes work outside. There are ~ 40 remote offices, which have a standard router, 1 PC via wire, 1 laptop via WiFi. Information is exchanged through the cloud, mainly various uploads for 1C, the load is small, but it may be necessary to look at CCTV cameras.
There is a task to raise the VPN and completely move away from the cloud, as well as to expand the possibilities of support and administration.
In the central office, remote clients must connect from their devices with authorization, there is a need for RDP, a maximum of 4 people at the same time, in remote offices, routers must be clients. Clients should not see each other.
The central office has a dedicated line with white static. In remote offices, there is a zoo of cheap routers with different types of connections, 50% 4g modems.
Questions:
1) What type of VPN to choose?
2) What to put in the central office?
3) What to change the zoo of routers in remote offices for (we tend to some keenetic)?

Answer 1

What's the budget? Requirements of certified equipment or do not care?
The simplest is mikrotik.
Take a more powerful piece of iron to the office, let's say ccr. In satellites 951
Choose the type of tunnels, again according to your requirements. Do you need strong encryption? l2tp/ipsec, no need - pptp.

Answer 2

1. Any, except pptp
2. Mikrotik. For example rb1100ahx2 - it immediately has a hardware encryption module
3. Mikrotik. For example rb450G or its more modern counterpart.
A network built on one type of equipment immediately removes a bunch (yes, even a LOT) of smuts. From typical configs to replacing failed hardware.