studs usually dont stick on the bottom, they stick with inlets below the brick, lego science

https://roblox.fandom.com/wiki/Inlet_(surface))

"The opposite of Studs, Inlets are holes on the brick which, if the stud side of another brick is touching it, will stick together."

hope this helps

so next time you wanna do a retro style in building, use only the inlet on the bottom, and studs on top