Faster than gigabit, but not 2.5 gigabit. Your cables likely support the speed, just your ports and switching hardware are capped at gigabit.

It's not extremely expensive, but unless you move around a lot of big files, you're probably getting very diminished returns, even spending less than twice as much for 2.5x speeds.

If you have only one device on Wi-Fi, multiplexing turned off, or especially if you have MU-MIMO support, Wi-Fi can be faster than a single wired connection. It is still higher latency and subject to other drawbacks such as security and power consumption, but of course it offers advantages that can outweigh the disadvantages depending on use case and user needs.

That said, it's technically not faster than the cable, but rather faster at the data link or network layer. For example, CAT8 physically supports up to 40Gbps, but most consumer and even professional electronics only support up to 2.5Gbps. Only really enterprise level switches can push up to like 100Gbps onto copper, and even then that's using QSFP transceivers, not RJ-45 connections. Fiber cables regularly push 400Gbps.

Impressive, I lose half my speed with the router around the corner.

Same lol. I get 800Mbps on Cat6, but 1100 on Wifi 6 with one of these fancy expensive 11000ax gaming routers that has all those antennas (antennae?).