I noticed that when I hook up my laptop to my modem via the cat 7 Ethernet cable, it gives the link rate of 1gbps(which I am expecting and should receive) but the moment I plug it into my orbi router it changes to (100mpbs). This was weird as when I tried a different cable (cat 5e) both gave a link rate of 1gbps. I am so confused on why my cat 7 cable won’t give 1gbps link rate to my router, but does on my modem.
Cables can be really strange when they fail. Some work on some machines but not others. It takes only a slightly loose connection and it will not work correctly. Although there are testing meters that will certify cable it generally is not work messing with. Your only option tends to be to cut off the ends and reterminate the cable. A very long cable it may be worth it because of the cost but other cable it is easier to buy a new one.
Be aware there is a massive amount of fake cable on the market. The words CAT6, CAT5e etc mean nothing really they need to be certified cables which they must pay for. Still you will find fake cable with eia/tia markings.
You need to always buy pure copper cable with wire size 22-24. Any cable that is CCA (copper clad aluminum) or is that thin or flat cable is not certified cable and does not always operate properly.