But that doesn’t work clicking on the ‘slots’ for the Sends, the OP’s main complaint at this point (for Inserts, yes - what you say is true…). But, as I’d said, if you Right-Click on the send level (slot) you’ve set up, you can then choose ‘Edit Effect…’ from the context menu, to get to the specific plugins UI.
Ok, not quite as elegant as a dedicated button I’d agree - but pretty good. 