Varieties of mushrooms in beds built with Hugelkultur

First Happy New Year to all! Hope you’re all safe and started 2023 well.

Thanks to the crazy weather we’re having here on in NSW, Australia, vegetable growing is completely out of whack. Cucumbers hardly happening, zucchini fruit dropping before maturing, not fun. Anyways, I’m not the only one struggling, I know that for sure. The question:
I have built up my raised garden beds with the so called Hugelkultur and I’m thinking there might be a nice culture of mushrooms living underneath my carefully created top soil. I’m getting some interesting fungi growing, from bright yellow to orange (the orange used in the top banner of this forum) to dirty white/beige coloured stuff (in pic). I also got some of those ‘normal’ mushrooms, the ones with stems but I’m not too concerned about those. It’s the creeping coloured ones (some interfering with my lettuce) that seem to be more of an issue. I’m not going to eat that lettuce plant covered in it but would the other ones be safe for consumption?
Stupid me put the hose on the affected lettuce, not noticing that the fungus was dried out already, with the water causing a cloud of brown dust going up in the air. Honestly. Could kick myself but that wouldn’t stop the spores drifting along so I just held my breath and watched the cloud disperse into the air. Lesson learned.
I’m considering topping up the beds with some good soil and then plant a cover crop and forget about it for fall and winter and start again next spring or is that too overly cautious?
Your input is would as always be much appreciated!

Very useful link, thank you Sanderson!
Re: hugelkultur: you’re absolutely right, not really compatible with SFG. I came across that before deciding on the SFG. On top of the branches and tree stumps, etc., there are straw bales and then there’s the proper mix. Nice in theory, not working in practice. I’m watching my beds collaps overnight and there’s no end to the amount of topping up and I’m starting to regret the hugelkultur slightly. Still considering to give it a season to let it rest, after following your advice and fill with sand, watch it sink and fill some more and then replace the MM.
Living and learning!
Thanks for replying to my post!

I recently saw a video of a raised bed that the bottom was filled with wood chips and then topped with a soil mix.  The wood chips decomposed so rapidly that the raised bed imploded from the weight on top of the decomposed chips.  Lesson learned there...

Thank you both for your posts! Some sand and topsoil it will be.
Luckily my beds are a size below needing the braces so at least I’m not facing that problem, the beds imploding because of the pressure. Other than that, nothing but positives on the birdie beds, very happy I bought them. Especially with all the rain we’ve had. Everything I had in ground completely drowned but the beds held up quite well.