I recently reinstalled, I previously had no such issues with any distro I tried (including endeavouros).
When I boot my computer 8 times out of 10 internet either doesn’t work or, if it does, the pink is absurdly bad.
A friend suggested I try using connman instead, that did not help.
When it connects to the internet well everything is fast and flawless.
You have Realtek 8168 hardware. I’d try uninstalling package r8168 and reboot. If that doesn’t help anything, you can re-install it easily (it should be in the package cache: ls -l /var/cache/pacman/pkg/r8168*