I remember as a kid marvelling at the thought of thousands of dollars. Imagine how much chocolate you could buy! Then I started dealing in thousands and my sense of scale increased. Hundreds of thousands because of property. Then you deal with multiple properties, and you've moved to the beginnings of millions. More properties, bigger projects and you're in 10s of millions fairly quickly.
Its kind of like starting out on a 14" monitor and then getting a 30" monitor. At one point was sheer amazement but after awhile of operating at a larger magnitude your sense of scale adjusts. You get used to it. Adaptation is real. That big monitor just blends into the background and smaller monitors seem quaint and constricted.
I sometimes deal with storages in the petabyte range. The number of drives and equipment required to get a petabyte currently requires significant construction. Under my desk is a 60TB array that was built in an afternoon. That used to be large. Now I treat that as just long term storage for a 16TB SSD array. That was unfathomably huge for a persistent ram disk. The first hard disk I bought as a component I installed was a 400MB disk. I remember when 1.4MB floppy disks were huge. Because I started out with 5.25" which held 360k.
Its all about expectations, utility and what you are doing with these numbers. If it helps, you can make up a unit of your own as a temporary placeholder. Eg if I was thinking about property as a developer then 1.5 million might be an "average property". Then I would mentally think in those terms. 15 million is then just 10 properties.
If 10 million is a rounding error and this still seems weird then you need to scale accordingly.
In reality, all the numbers we use are huge, we just don't see it because of the units we talk in. Eg an ordinary orange or apple is made of millions of atoms. But you aren't overwhelmed because you think of it as one piece of fruit. You feel no problem having and thinking about a dozen pieces.
A slice of an apple can be seen as a rounding error compared to a dozen apples. How many water molecules are in that "rounding error"?