So far I could not use anything in the BTC wiki.
From the technical point of view we find quite a lot of more or less superficial descriptions of this and that.
Still missing an equally exact description of the "surrounding" "block".
I reject your claim that nothing in the wiki is usable. It really does contain everything that you need to understand a block. Just takes some getting used to...

The "surrounding block" is described exactly above. There is some confusion on exactly what parts are block and which parts are message. Most people consider the block proper to be "header + NumTx + TX
0...NumTx". In practice, you'll pretty much never find those stored or communicated without the magic number and the size, except when using the RPC calls that return block bodies.
Keep in mind that bitcoin is nested, and a lot of the complicated bits are in the interactions. The block itself is very simple, a short header followed by a list of transactions. Transactions are simple too, a header (really just the version field), a list of inputs, a list of outputs, and a footer (just the locktime field). Inputs and outputs are where things start getting strange, but even those are pretty simple in representation.