Love aluminium extrusion. I have a sim rig made out of it and the channels are dust collectors, which can be quite tedious.
I've used the metalstore.co.uk to make a unit like yours. Used the 25mm box section and clamps. Basically Meccano for adults.
I noticed that they seem very popular in sim setups! Very cool. After the stress of doing the measuring myself, the building part was enjoyable, as you said it’s like Lego/Meccano.