Hello I am having issues with specifically chaotic-aur. Download speeds are 200-300 KiB/s but with others 7-8 MiB/s. I couldn't find any options on pamac gui. I also tried the solution of this topic Slow download speed using pacman but it didn't help me and I am having issues with chaotic-aur.
Thanks for the help.
First of all welcome 
Chaotic-aur is struggling a bit currently because 99% of the people using this distro are probably using the main server
There is something you can do however: edit /etc/pacman.d/chaotic-mirrorlist and put a # in front of the mirrors you do not want to use. I think our mirror was reported to have good download speeds lately so you might try that one.
Then run pacman -Syu again 
Currently trying to think of a good, userfriendly alternative. Powerpill might be an option too.
First of all thank you. As mirrors I have these and both uncommented. I don't have any other entries. How can I find other mirrors?
Server = https://chaotic.tn.dedyn.io/$arch
Server = http://chaotic.bangl.de/$repo/$arch
try to play around with different mirrors in garuda assistant's refresh mirrorlist feature
I've commented the Netherlands and its all fine now. Thank you again!
just fyi, thats the whole file with all mirrors:
# Brazil
## By: PedroHLC and UFSCar
Server = https://lonewolf.pedrohlc.com/$repo/$arch
#Server = http://lonewolf-builder.duckdns.org/$repo/$arch
# USA
## By: GarudaLinux and Fosshost
#Server = https://builds.garudalinux.org/repos/$repo/$arch
## By: LordKitsuna
#Server = https://repo.kitsuna.net/$arch
# Netherlands
## By: Var Bhat and LiteServer
#Server = https://chaotic.tn.dedyn.io/$arch
# Borgos, Spain
## By: JKANetwork
#Server = https://repo.jkanetwork.com/repo/$repo/$arch
# Germany
## By: ParanoidBangL
Server = http://chaotic.bangl.de/$repo/$arch
# Seoul, Korea
## By: Ryoichi <t.me/r377yx>
Server = https://mirror.maakpain.kro.kr/garuda/$repo/$arch
Glad it helped.
Welcome to the forums @KomFlag 