Other providers downloads at 40-50 MB/s (mega bytes not bites), while Netflix struggles at less than 1% of that speed - 300-400 kb/S (bites not bytes). Restarting app did not help.
Any ideas?
Maybe a location issue. Maybe some connection between you and Netflix. Maybe you are using a VPN?
Netflix downloads fine. US, no VPN, 1 gig internet connection,

Consider try changing DNS:
Provider Primary DNS Secondary DNS
Google 8.8.8.8 8.8.4.4
OpenDNS 208.67.222.222 208.67.220.220
Cloudflare 1.1.1.1 1.0.0.1
Or power cycle your Internet devices, my ISP always needs that done.