It shows low signal to me too but my connection speed is even better on any Linux distro (and it shows low on any Linux distro), than on Windows, besides that (I think thats only a graphic problem), if your connection works bad, identify which is your wifi device, and then which drivers that device use... Probably an ugly Realtek one. Use WikiDevi page to search drivers, all free and open source.

thank you. I will give it a try. I tried to download VLC from deepin store but speed was just 127 KBPS. I have 25MBPS plan.

Thats probably a mirror problem, run a test of available mirrors at control panel, then select the one (when the test ends) that appears on top of list. And, even if deepin store exists, is more better and cleaner to install apps on terminal, running sudo apt install *name of app*.