Part of the Furniture
L2TP by itself doesn't have any encryption. You basically only change your external IP to the one of the exit server. Your in/out data is visible and you can be blocked at any time on a simple firewall. My suggestion is to switch to encrypted OpenVPN. You'll have significant speed drop though, perhaps down to 70Mbps. This is what AC5300 can do. For more you need a newer ARMv8 CPU router with AES support. You may get to 200Mbps speeds. For even more - x86 hardware firewall or change of protocol to Wireguard.