Hi there, bro. I have the same problem
)) I've done some network sniffing and I've found that splatoon 2 uses Amazon cloud, so it would be futile trying to find all ip adresses, there are a lot of them and they are moving.
Anyway, I've found this IP - 54.68.201.173 (which is blocked by RKN). This network is huge - 54.64.0.0 - 54.71.255.255. But anyway I've added it to my VPN routes and Splatoon 2 now ... sorry, STILL DOES NOT WORK... Stay tuned
UPD: Finally, it works (at least once) on my home inet
I've enabled dns logging, some resolved IPs were banned by RKN. But adding their network hasn't help. Then I've googled info about banned Amazon network addresses, added them to my routes and voila! So, there are my routes (for openvpn.conf):
#amazon (splatoon 2)
# g2df33d01-lp1.s.n.srv.nintendo.net
route 54.64.0.0 255.248.0.0
# receive-lp1.er.srv.nintendo.net
route 52.192.0.0 255.224.0.0
route 34.192.0.0 255.192.0.0
# random amazon nets from telegram
route 52.58.0.0 255.254.0.0
route 18.196.0.0 255.254.0.0
route 18.184.0.0 255.254.0.0
route 18.194.0.0 255.254.0.0
route 35.156.0.0 255.252.0.0
route 54.160.0.0 255.240.0.0
try them and post a reply if they helped! Surely with so broad route rules your VPN server will get a lot of your traffic, so be careful and watch for traffic limits!