I finally bought a Mogics MA1 adapter, got a deal on it (~$15). Good Adapter, looks well designed and built.
(I do not need the Power Bagel’s multiple ports, so just the adapter is sufficient.)

I find it works better than the Kikkerland / Road Warrior design as it is shorter than that design (though has a wider cross-section), and at 25g is lighter too; also, the Kikkerland blocks adjacent ports with the US/JP or AU configs. The MA1 only takes US/JP plugs, can be managed by only buying straight-prong plugs.

It does hold my Innergie 60c much better too, as the 60c tends to lever itself out of the Kikkerland socket - the shorter & wider profile moves the centre of gravity closer to the wall while also giving the 60c a bigger area to push back on the downward torque.

Think the MA1 may have difficulty with recessed Europlugs & the like (e.g. Swiss) - the adapter does have telescoping prongs, but not too sure how strong they are to hold the weight of an adapter. I will probably just continue to carry Kikkerland, or maybe just the front bit; will see.

(On an aside, my father apparently got a Road Warrior 2 decades ago… found it in his box of electronics, though he doesn’t remember exactly when from. Same design, just made of this see-through plastic, which is kinda cool for the rounded plugs on springs.)