@Hans_Lammerts it is not so complex. IFC lets you fill out the eastings, northings, and elevation as a text tag, and also nominate a coordinate system just like in your screenshot. Also, as you say, IFC discourages lat/longs, though it does let you nominate it for “convenience / reference only”.
The additional information you can record in IFC, also as a simple text tag, is an angle rotation, and a scale factor, both of which are required in the discipline. Also, it allows for you to go into detail on a coordinate system, which is required for custom coordinate systems used on complex jobs. That seems to be missing in your screenshot, but it in no way makes it complex in my opinion: just a few more text tags.
In Tekla, from memory (I am not experienced in Tekla), filling out that form will set the text tags necessary for a correctly geolocated IFC4 file.
The reason it seems so complex is because vendors have done a bad job implementing it, and perhaps correspondingly, the certification process either does not address this, or addresses it poorly (I do not know - the certification process is opaque).