Yes, but you need 2.5GbE WAN port + 2.5GbE LAN port. Very few consumer routers have more than one 2.5GbE port.
Here is an example of one:
Dual-Band WiFi 6 Gaming Router, Dual 2.5G WAN/LAN ports, enhanced hardware, WAN aggregation, VPN Fusion, Triple-Level Game Acceleration, free network security and Mesh WiFi System
rog.asus.com
Routers with single 2.5GbE port (used as WAN) can eventually achieve >Gigabit
aggregate traffic to multiple devices, but no single device will get above 940Mbps when connected to Gigabit ports. Gigabit on Wi-Fi is tough as well, you need clients upgrade to AX and 160MHz wide channel support.
Your ISP speed change/upgrade is only dragging you to spend more money for no reason. What more you can do with 1200Mbps compared to 900Mbps? The 2-3 seconds saved time in downloads will cost you $500 or more. The Internet browsing experience >100Mbps is all the same. You decide if it's a good idea. I would upgrade the router for better Wi-Fi, not for 2.5GbE port option.