Advice on DECxxxx upgrade for 1.5Gbps internet connection PPPoE and OpenVPN

[Rickvds]

We have been running a DEC620 OPNsense router for several years that we are very happy with. Our old internet connection was 100mbit for which this hardware was sufficient. Our new connection is 1.5gbit, so time for some new hardware.

The DEC620 only has gbit ethernet ports, so obviously it is not up to the task. Our new ISP uses PPPoE protocol, I read somewhere on the forums that BSD based systems can only utilize a single core with this protocol, limiting the performance. However, I tested the new connection and saw it can do 600mbit with this hardware.

We also run an OpenVPN server on the router. With the DEC620 the speed is only around 70Mbps. One of our goals is to increase this, but it is hard to judge from the specification what the expected speed is on other hardware. Also, maybe OpenVPN is not the best VPN to run for performance? Advertised IPsec speed for the DEC620 is 600Mbps, but SSL VPN (whatever that is) is only 170Mbps

I really don't have time to build a custom machine, so I am looking into buying one of the DECxxxx routers. I am considering all types with 2.5gbit ethernet ports.

DEC620 1gbit IPsec 600Mbps (old router for comparison)
DEC740/DEC750 2.5gbit IPsec 1.2Gbps
DEC850 2.5gbit IPsec 2.5Gbps
DEC2752/DEC2770 2.5gbit IPsec 1.2Gbps
DEC3852/DEC3862 2.5gbit IPsec 2.5Gbps
DEC4240/DEC4280 2.5gbit IPsec 2.5Gbps

Does anyone have any experience with this hardware in similar configuration?