1. As a network guy, I believe you are going to be hard pressed to get 1000Mbps outside of a lab certification network stack. Between two reasonable Gigabit devices with a crossover cable or through a good network switch, you should be able to get about 950Mbps using iperf with Jumbo MTU frames.
2. I used to be able to get a download result of about 950Mbps on the original Rogers Speedtest (https://www.rogers.com/customer/support/article/internet-speedtest) while on Rogers Ignite Gigabit with the Hitron CODA 4582. After the switch to the XB6 and from a directly connected (Gigabit Ethernet) computer, I am unable to get above 500Mbps on Rogers Speedtest. However, I suspect that is a problem between the Rogers TV Intranet and their Speedtest site. Using the Ookla Speedtest App on OSX, gives almost a 950Mbps result.
3. Recognize that 1000Mbps is the maximum in the best case scenario. To test that, you need to be directly cabled in to the first device (XB6) with at least a Cat5e cable and no interface errors. Adding the eero, connecting through a switch or using WiFi will not improve on that result. You will not be able to reach 1000Mbps using the eero WiFi (802.11ac).
4. The best eero Speed Test results I have in my history are in the low to mid 900's. I always have upload speeds greater than 30Mbps.
5. Rogers uses marketing speak to provide "a maximum download speeds of up to 1 Gbps for Ignite Internet Gigabit." They know it is not possible to deliver 1000Mbps even in the best case scenario. Also recognize that since they deliver Ignite TV and Home Phone through the same Gigabit Ethernet cable, it is not possible to get 1000Mbps Internet at the same time; the math just doesn't work. As an aside, commercial providers will put you on a 10G interface if you order a 1000Mbps service.
So to answer your question: you are never going to see 1Gbps on the eero Speed Test regardless of configuration. You may get a high number (950Mbps) if you disable the WiFi and other devices so nothing is competing for the bandwidth.
Edit: For typo.