Ethernet cord plugged in yet has the same internet as before
(I think I picked the right flair?) I just plugged my brand new Ethernet cord into my pc which is from my bedroom to my garage and I thought it would be my saving grace due to me upgrading my router and getting two different types of extenders. When I initially turn on my pc with my Ethernet cord plugged in I get around 600-800 mbs yet after about the 2-3 time of testing the internet speed it goes down to 1-5 mbs and same for the upload speed with some times the upload speed being higher than the download speed. I already downloaded the latest motherboard driver and tried the easy fixes by unplugging the motem and router for a couple minutes and trying again and then I unplugged the Ethernet cord for about five minutes yet that didn’t work either. I just need some type of advice for what to do as I’ve already tried everything from that youtube and Reddit have said