Tiled shower base on timber floor

I would like to have a tiled shower base on timber floor.

I’ve read a lot about how this is done and spoken to a couple of tradespeople. Initially everyone says: we will do it, no worries. As conversation goes along and I mention possible leaks etc they always say – I’ve done a shower base in my own bathroom, or “just get a shower base, it’s safer”, or “lowering the floor lots of work etc.

I just see no confidence unless I go for really expensive waterproofing solution, say $1500 just for the shower base – see The Atlantis range of tile shower enclosures and tiled shower systems for example

For safety reasons, I was ready to decide on acrylic shower base which I don’t really like.

Here is the alternative: shower base designed to be tiled on. The Universal Shower Base
They have a 1000x1000 shower base for $450 - this is not too bad!
I won’t even bother with lowering the floor. I’m happy to have a hob as soon as it’s all tiled and safe from waterproofing point of view.

The only issue Universal Shower Base does not make corner 1000x1000 showers.
Are there any alternatives?