Matt_SD wrote
According to TP-Link support "the VPN is only available in router mode to be passthrough".
Very surprised to hear this!! Haveing been running this setup with another brand for years without issues...
@Matt_SD
Something must have been lost in translation. There should be nothing in Deco running in AP mode to prevent VPN connectivity. Because you've got this type of an answer, you may have to do investigation and troubleshooting by yourself.
I am assuming you run Checkpoint VPN client on laptop, if you can have it both connected by Ethernet and by WiFi. Start with the following test: enable WiFi on your ISP router, power off Deco X90s, connect laptop to router WiFi, check if VPN is working when connected by WiFi directly to ISP router.