Agree, I was thinking about using a carbon fiber tube set ups using scope rings to attach but this looks more refined, particularly if you can split that adapter.
Making sure you understand…
There is a “Shiewee” $37 adapter from Amazon. This converts your Picatinny rail to Arca. Its only 60mm long - this is important because you don’t want one that is longer than 60mm.
The AliExpress $40 “BEXIN” set consists of two arca clamps that are screwed together, you can easily separate them- its just two allen screws. It also consists of an Arca 400mm rail that is Arca on both TOP and BOTTOM.
You can buy the double Arca clamp without the 400mm rail for just $12.85 (incredible quality- amazing what you can get directly from China)
Yes, you could just buy the Shiwee $37 adapter, or this one for $32, and screw a long Arca plate to it - with the arca side facing down so that it can attach to a tripod. This $32 adapter has two screw holes in the bottom, so using both might work better if you are trying to bolt a plate directly to it…
Zelnoox Picatinny Arca Swiss Plate,Picatinny Rail to Arca Tripod Mount,Picatinny Rail Converted into Arca RRS Dovetail Adapter, Compatiable RRS Really Right Stuff Tripod Mount
https://a.co/d/5jp7LnA