Well, I share your disappointment
I chose this Http-Request project for its simplicity and ease of implementation with the plugin.
I hadn't even noticed the program pause waiting for the answer because it happened only once, when the model was installed, and when the additional models were loaded.
While waiting for the completion of the various loads and the positioning of the space station, a second block goes unnoticed.
But I was aware of it because this simple implementation of Http-Request acts in a "synchronous" way, that is, it waits for the completion of the operation before giving back control to the normal program flow.
To have a more performing performance, and not to notice that the call is taking place, you should look for a project that produces an "asynchronous" call.
This does not mean that the request for data takes place in a shorter time, only that, once the request is made, the control is immediately returned to the main flow of the program, the data is downloaded only when it becomes available and the user does not he notices all this "underground" work because the program shows no interruptions.
Ideal, famous and now ultra-tested, it would be the CURL project (it can work asynchronously and with SSL encryption) but we have found that it is not easy to include in the Outerra plugin.
Perhaps, with patience, another Http-Request project could be found that possesses these characteristics and is easier to implement ...
I take this opportunity to congratulate you on the speed of development of your Multiplayer project which is already beginning to produce tangible results.
Good work!