unable to add a device to my account says offline all the time. garbage support as usual.
So I see you have found the Sonoff "Smart Home" forum
In the Smart Home forum, there is an FAQ thread in the Announcement section.
Read the FAQ to see how to get support.
Posting in the Smart Home forum is a statement from you (a Sonoff community member) to other members of the Sonoff Community. It is not an ask for support. The FAQs will tell you how to make an ask for support. And yes, I presume you will need to wait for support to come back from their Holidays: As noted on the itead.cc website, Chinese New Year is from Feb 11 to Feb 22 inclusive, so they will be back from Holiday on the 23rd.
However, your issue can generally be solved via FAQs and manual without the need for an actual support staff member.
Server issues is not the norm. There are indeed postings from people that do not read the manual. There once was a real server issue a few months ago that effected on region of global on only the Amazon AWS service, but again far from being able to classify it as the norm. Amazon has since rectified their issue that caused the problem.
Depending where you purchased your devices from makes a difference. When purchased direct from Itead via the itead.cc website, you can be guaranteed they are New in Box and never before registered. When you purchase from somewhere else, you can not be guaranteed this New in Box and never registered. If a device is already associated to another users account, then in this case you will need support staff to fix for you.
Your claim of 5 million times can not be believed, it would not only place your initial attempt before the Sonoff devices were even first created, but such erodes the credibility of any other statement you then make.
Sonoff indeed does not point to Nextion.
System is not garbage as you claim. But asking in the correct place
(and not public forum) indeed needs be first step to getting proper
support. Like putting a note on a bulletin board in a marketplace and
avoiding the service desk all together. Sorry, go to the Service Desk
as indicated in the FAQs.