ᐅ Boundary Construction Garage – L-Shaped Concrete Blocks Under Slab – Any Experiences?

Hello community,
I have a question and hope for your expert advice.

• See attached image
• Our building project involves constructing a double garage along the left property boundary with the neighbor.
• The plot needs to be leveled, so we have to install L-shaped concrete blocks on the left side, which will result in our property being higher than the neighbor’s.
• Up to the L-shaped blocks, the soil must be replaced with crushed stone and compacted (soil replacement according to the soil report requirement).
• Afterwards, a concrete slab for the double garage will be poured on this base.

Now my questions:

• Is it possible, safe, and practical to build the concrete slab including the double garage on this base as described (concrete L-blocks and compacted crushed stone)?
• We are concerned that structurally it might not hold or that the crushed stone could settle by a few millimeters, causing the slab to crack. Are these concerns justified or is the risk minimal?
• Is this the usual practice or is it done differently in reality?
• Do you have any additional advice for us?

Thank you very much and best regards.
I look forward to your feedback.