Coax Signal Strength and Wi-Fi

I have an RG-59 75 ohm coax cable going through a splitter or two, and a coupler, then going into my router. I’m using gigabit internet (1200mbps plan) and I also just bought a brand new modem/router combo (Motorola mg8702) for gigabit internet. I have my pc connected to the gateway with cat 5e Ethernet and I am getting ~940mbps. However, Wi-Fi on my phone is getting ~96mbps. I’ve read that getting a coax with a stronger signal would improve Wi-Fi, or at least improve packet travel. Is this true? If so, how does packet loss relate to internet (Does it reduce page download time? Does it reduce speed? Does it add latency?)? If this is absolutely not true, then what would having a stronger signal through coax do for you? I don’t mean numbers, like what literally would it improve? 

Also, how do I improve my Wi-Fi speed? I already have a mesh network, and 96mbps on a 1200mbps sounds pretty sorry to me. Please try to simply responses as much as possible, as I am extremely illiterate when it comes to tech and its technical terms. Thank you very much.