No for a number of reasons.
First the route/modem likely only has gigabit lan ports much like your current router. It might have a 2.5g wan port but that just means 2 lan ports can run at 1gbit not a single lan port can run at 2.5g.
I know of no powerline unit that has 2.5g ports...some moca devices do.
Your end device likely has only gigabit ports and even if it does have 2.5g ports if you plug it into a powerline with 1gbit ports it will drop back to 1gbit
Much more important the very fastest powerline units are lucky to get maybe 300mbps and many times less because of how the electrical wires run.
Finally many things on the internet can not go that fast. Many servers have artificial limitations to prevent someone with a fast connection from monopolizing all the server bandwidth. Others there are other technical limitations. Many applications say netflix or youtube only use what they need, like 30mbps max, and will not perform differently on a faster connection.
In general most people don't need more than 100mbps. Faster connections are nice if you say download some very large game but how often do you actually do that.