I have a Dell Inspiron 15 3567 laptop which only connects to wifi when close to the router but usually stays connected after that. However, it sometimes disconnects from the router -even though the router fairly close- and I have to repeat the process of getting super close to the router to reconnect.
My adapter: Qualcomm QCA9377 802.11ac Wireless Adapter.
P.s. I have unticked the "allow the computer to turn off this device to save power" and the problem hasn't been fixed yet.
Personally, I feel the Qualcomm QCA9377 802.11ac Wireless Adapterere's is just rubbish. Even my connection would range between weak and strong all the time. I think the best solution for you would be to swap it out. You can go with the Intel AX200NGW.
But before you spend money on this, do check if all the laptop wireless settings are fine, same with the router as well.