Watched the video, it's not on your end, technically....
This is what it looks like when servers are overtaxed by the 70.7 limitation.
Your not lagging yourself, the server isn't sending you data fast enough to mark the real time positions of other players.
Rubber banding, freeze an then warp video, spurts of both, long load times when porting to new areas, or dungeons that are not normal. Casting a spell or moving in a direction an not reacting till 3 sec later. Zoning into a city an players or npc's have not loaded to interact with. (takes an extra 3-4min to load), these are ALL server-side problems.
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My brother had one of the largest usa multiple-game servers for over 10 years, you pay more money in bandwidth (100k) than server upgrades.
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I think World of Warcraft stated once they paid 2-3million dollars a month for bandwidth alone with over 9 million copies sold.
Since SE turned off digital downloads, an forbid new character creations, they exceeded the safe 70.7% server load, so now when their full, the cpu's are pegged out from 90%+++
this is why we have all sorts of errors, lag an such, errors etc.
Their going to have to physically buy 1-2 more servers (per region) an transfer some worlds over to them, with new tunneling and or buy more bandwidth, or the servers are going to continue to be this way for months.