Hey there. I recently had a similar issue this week when I installed Plasma on my laptop dual booting with Windows . Seemed to be an issue with Wifi signal. I did a couple things that worked, but it seemed like a bit of a random issue, so I'm not sure if it was just my individual situation or not.
1) I turned wifi power managment off. I found my wifi was dropping signal constantly then signalling back up by the second. I first turned off Wifi power managment off, this helped right away and the connection was more solid & not dropping in and out second by second. This can be done in the terminal (wlp2s0) is my wifi configuation setting, you will have to determine what yours is.
$ sudo iwconfig wlp2s0 power off ### /etc/rc.local
My internet was still slower than usual after this --- But much better than initially -- I have another wifi internet service network for an office, that I tested connecting to, and it worked perfectly, but my normal internet connection for home use was still slow. I never had this issue on windows, but for some reason on Solus this particular wifi connection was much more sensitive to proximity. My location was a fair distance, but like I said this wasnt an issue before. Not sure why it is now. I rearranged by wifi set up to put it in a little more central location, closer to where im generally using my laptop and it now works perfectly fine. Using a device to boost wifi would help as well, if re-arranging your set up is out of the question.
Hopefully this helps. Good luck
