Connecting to L2TP over IPSEC begind the Orbi SXR80

Some details to check:

• Windows Firewall has separate rules for private and public connections.  The LAN created by the router is a private IP subnet, typically 192.168.1.x.  A connection from the internet will be a public connection.  First step: check the Windows Firewall settings.
• The router address (IP2) must be a public IP address, not a private IP address
  (https://en.wikipedia.org/wiki/Private_network )
  When a customer router is connected to an ISP device that is also a router, the ISP router will assign the customer router a private IP address. a "Double NAT" condition.  This interferes with a number of specific applications, including VPN.
• Those appear to be the correct ports. Some require TCP and some require UDP.  (I believe the most common practice is to forward both TCP and UDP.)

It is creative to host a VPN server on a device within the LAN.  As you are probably aware, the SXR80 router has a feature to create an OpenVPN host, which will allow access to every device on the LAN. See page 112 of the User Manual:

https://www.downloads.netgear.com/files/GDC/SXK80/Orbi_Pro_WiFi_6_UM_EN.pdf   This feature would be affected by Double NAT the same way that a the Windows server VPN would be.