Threaded insert, screwfix. Don’t trust the suggested hole size, try various holes and a scrap piece +\- 0.5mm from suggested. Harder wood needs a slightly larger hole or you can snap the insert putting it in.
Here's something which could go hand in hand with the use of these things.
Backwards drillbit ala Frank Ford, great for neatly and accurately sinking a hole for the head of suitable bolts, works great in hardwoods, but alas no piccies of that.