Minecraft – How to extend the length of the DaylightCycle on a Java Edition Spigot 1.16.4 Minecraft Server

I assume you are referring to a BungeeCord server which is a bit of an undertaking to setup. Most minigame / servers with a "hub" use BungeeCord as it allows much more players to be online consecutively- the trick? they are all connected to different servers which are then connected to each other using the bungeecord software. This is a pretty good tutorial, but be advised it was created by a server host- although the instructions are pretty universal and can be adapted to any host you use.

Autocrafting is a much requested feature, but not one that currently exists in Vanilla Minecraft. Many mods add it, but all of them in their own way, so there is no general answer for those either.

Some people, like members of the Scicraft server, have automated crafting as far as possible, by building a redstone machine that puts a shulker box full of resources in one spot, letting their computer use a click macro to quickly take items out of it, craft them and put the result back in, which the machine detects, crushes the shulker box and places a new one, repeating the cycle.
One tutorial for such a machine is here (disclaimer: I have not watched that video myself, I just know that type of machine and that Ilmango has used them in the past).

A lot of items that are usually crafted can also be automated in unusual ways. For example bowls drop from turtles (which can be bred by holding one button) that get struck by lightning, endermen can hold melons and drop them as full blocks when killed, fishing and mob drops can give you lots of different items that would usually be crafted, including leads from wandering traders and so on.
In theory you could even farm raids or patrols, then convert the pillager banners to banners with one less layer on them using cauldrons by dropping the banners onto you while holding the "use" button and looking at a cauldron, which gets occasionally refilled by rain, then repeat the process more times to remove more layers. That would be a way to farm a theoretically infinite amount of white banners (very slowly) without needing a click macro.
But there is no such method for cake.