Teh Pizza Lady

this is the solution I would also recommend if you want to ride together. However if you're intending it to be a community elk, I would build a stable to keep the elk contained and prevent it from wandering and then just keep the flute and medallion in the elk's saddlebags when it's not being used. Best of luck!

I recommend getting https://mods.vintagestory.at/simplehudclockpatch for starters. It's simple, out of the way, and can be added to any existing game without much fuss. Also https://mods.vintagestory.at/show/mod/25352 is really good if you struggle with finding items that drop from doing things like mining, chopping trees, or farming, since these items don't bounce and rotate like they do in the other block game. Also if you're a red-blooded American like me then this mod is a MUST HAVE:  https://mods.vintagestory.at/freedomunits

First let me welcome you to the forums @Oulana! I hope you enjoy your stay here!
Secondly, I believe there is a command you can run. From the wiki on this topic, you can run
/wgen pregen [radius] to pregenerate chunks around the player. Take care as this can cause a massive lag spike if your server hardware is weak enough that you need to pregenerate the chunks to make the game playable. This process will also take some time, which is a valuable commodity in VS as I'm sure you'll see, so I wouldn't go this route unless you're having issues with the server lagging as people go exploring.
Wiki link:  https://wiki.vintagestory.at/List_of_server_commands/wgen

Looks like your host is partially correct that they personally don't have any issues. But their ISP is certainly having issues. I would forward them this information as well as this screenshot:

While the ping to your server is fairly steady (it will always fluctuate depending on what the server is doing at that moment), it appears that your host's ISP is causing the pings (and therefore the communication data that VS requires to keep you on your server) to get lost in the magic black box known as the internet. It looks like your host uses aurologic.net as their ISP. I'm unsure what rules Germany has about internet connections stability, so I'm not sure what leverage you have here to getting this fixed, but I would label this "unacceptable" if it happened over here in America.
Hope you see some resolution and happy gaming!