@Calli Factory reset helped. Speeds are back to normal. I had to rebuild the network from scratch after factory reset, but that wasn't a big deal. Thanks @Tony

@Tony Hi Tony, Thanks for your message. I already tried that - set the Deco in Router mode, in the QoS edited the download speeds to 100, tested, then tried 1000, tested. Unfortunately, it had no...

I noticed a significant drop in download speed on my Decos after recent firmware update to 1.4.4. Both 2.4 GHz and 5 GHz bands are affected. Normally wifi on my modem/router is turned off, Decos are...