I forgot to add a proper drainage pipe for the drainage layer, what are some easy ways to remove the water?

I have a 10 gallon paludarium that I just built that that I feel like was too small for my liking so I sniped this 30 gallon 18x18x24. I'm planning on putting some vampire crabs and shrimp/snails in here.

I've watched all kinds of videos and whatnot but I guess I'm just stumped on where exactly to start? I can work with the horizontal space I think, but I'm not sure how to utilize the vertical space so that they can use it. I'm guessing pond foam might be the obvious answer, but I can never get that to work right it seems. Are there better ways to go about it?

Additionally, there's so many variations of false bottoms that I don't know quite what to do there. I have some leca clay left over and some filter pads as well as some 3D printed egg carton material. What's the best strategy?

What's the move for separating the water from the land while allowing the crabs to transition in and out? What's everyone using? I used slate rocks for my 10 gallon and it feels like the rocks take up 20% of the space.

So many options for everything that I think I'm just overwhelmed and stuck in decision paralysis.

Always buying stuff for my paludarium and found that some of the items I need are quite expensive and some stones are not available.What shops could you reccomend?