Texture details are based on the computer connecting to the server, not the server itself. The server has no reason to render textures and does not send such information to the players which connected to it.
You don't need two PCs. You can run a dedicated server, then run the game and join your server all on one machine. Just make sure to set the server with /norender. Also, playing as a LAN game should help with some of the lag, though you won't be playing aganist people online.
(I may not agree with thoughts posted under this name)
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