An Alchemical Gauntlet is not a Base Weapon, so no runes can be added to it. I guess this is an oversight, just like Alchemical Crossbows had not been proper weapons when they first appeared in The Fall of Plaguestone adventure, but were later updated.
Until the update happens, is there any permanent way to use the extra 1d4 damage while I want a +1 on attacks?
Would a Handwraps of Mighty Blows work?