You laugh but I recently had some floats but they didn't do exactly what I so I tried to make a flexbox sized to content, and it occured to me that I just want good old table to align my items.

i m dead serious. i use tables even with bootstrap, i like the way they gracefully realign between horizontal and vertical modes in mobile. (e.g. here https://coinzaa.com/)

Tables are great. I believe that all these grid systems will end up reinventing tables 100% anew.

I propose that they add new elements to HTML instead, <grid> <gr> <gd> etc. They will work 100% exactly like tables, but semantic people won't feel guilty using them.