BCM43142 Poor Connectivity and Range In Mint 19.1 x64

[Nafis]

My laptop is an HP ProBook 450 G3. I have clean installed Mint 19.1 on a separate hard drive only recently, and all drivers work fine, except for the wifi.

The signal stays around 60-70% right next to the router, and the internet is only barely functional; it will abruptly stop connecting with a site for a few seconds and resumes loading. If I keep the laptop open for an extended period of time (~5 hours), the wifi disconnects. In windows, I'd get 40% connectivity from the guest room (a distance of 7 meters and obstructed by four walls). This is frustrating in loading videos online, especially on Netflix and YouTube.

I am currently using the bcmwl-kernel-source driver provided by default in the installation. I have tried using the drivers broadcom-sta-dkms and firmware-b43-installer, the first of which made no difference and the latter broke my wifi completely (which I later fixed). I tried ndiswrapper with and without ndisgtk, which also did nothing. I even nuked the system by formatting it to hopefully shotgun any issues, but to no avail.

I am really on the verge to get a cheap usb wifi dongle, just to get the job done, unless anyone here can help me out.

Here's inxi -i for anyone that needs it

Network:
Device-1: Realtek RTL8111/8168/8411 PCI Express Gigabit Ethernet
driver: r8169
IF: enp2s0 state: down mac: dc:4a:3e:e0:bb:03
Device-2: Broadcom Limited BCM43142 802.11b/g/n driver: wl
IF: wlp3s0 state: up mac: 60:6d:c7:ed:5a:3f
IP v4: 192.168.0.104/24 type: dynamic noprefixroute scope: global
IP v6: fe80::626d:c7ff:feed:5a3f/64 scope: link
WAN IP: 103.112.169.2