D
Dumbo
I've often though about something like that instead of drilling and plugging and the associated risks and obs can't do that with underrated screed .These will help some folk who struggle with self levelling.
I have no idea what they will cost but I saw them the other day and I bumped into the Tile Rite rep today...... (no freebies either)
TileRite - https://www.tilerite.co.uk/general-tiling-tools/miscellaneous-tools/floor-levelling-pegs/