I don’t understand what this post is about, what does it mean “I can use the bots at separate servers”???
if by that you meant you don’t want to use a public instance of a bot that someone shared, then you can self-host them, most of them are open source, several can be found here: DeltaChat Bots · GitHub
you don’t even need a server, I will not enter in deep details but you can even host bots in your android phone using something like Termux app and similar: Termux | F-Droid - Free and Open Source Android App Repository
if you have a Linux desktop it is also possible to run them there at home, no need to pay for any VPS etc.