Here is a link re. ponds, etc. https://www.hedgehogstreet.org/help-hedgehogs/helpful-garden-features/
But I think shallowly sloping beaches are the best thing and if it is a large pond, more than one beach might be handy for the hogs. You might still be able to see on i player the pond made – as part of garden watch on Springwatch. That had a beach at both ends with pebbles. Having plants right up to the edge might also be helpful.
I have some ponds in Tubs, which have vertical sides, so I have raised pond baskets filled with stones/pebbles in them to make ‘beaches’ (partly under the surface of the water but with stones, etc. sloping upwards, some with shortish plants in as well). Also bricks piled up at the side in a sort of staircase to facilitate escape. Amazing what you can fit into a small pond as well as plants!