The "point of failure" is likely the hardware itself, as the MacBook Pro you're using shipped in autumn 2006. Comparing the specifications of a fully loaded, top-of-the-line MacBook Pro for that year to the recommended hardware for Elementary OS we see this:
||MacBook Pro (2,2)
||Intel Core2Duo T7600 @ 2.33GHz
||Recent Intel i3 or comparable dual-core 64-bit processor
||The Core2Duo is nowhere near a recent Core i3 in terms of performance.
(Upgradable to 4GB1
||The UI for Elementary (and anything that uses Gnome) requires a good bit of memory. 4GB is the minimum if you're a patient person
||ATI Radeon X1600 w/256MB RAM
||Integrated or Dedicated graphics card with 384MB RAM2
||Modern Gnome-based UIs generally use about 512MB of video RAM for general computing at 1024x768. Your MacBook has a 1440x900 display, so will need a bit more.
||A mobile 4200RPM drive from 2006 can generally move data at about 48MB/sec if the segments of each file are sequentially lined up on the disk (not fragmented). The slowest SSDs can generally move three times faster at a minimum.
It's almost a certainty that the MacBook Pro you're trying to install Elementary OS onto has seen some upgrades over the past 15 years but, even with 4GB of RAM and a modern SSD3, the system will struggle to handle the number of processes and services that Elementary (and modern Ubuntu) will try to load.
Based on experience, Elementary OS needs to have a 4th Generation Core i3 or a 3rd Generation Core i5 at a minimum in order to install. Atom and Pentium-based systems are pretty much non-starters regardless of how much RAM and storage is made available.
With all this said, if you really want to use Linux on that notebook, you may want to consider installing Ubuntu MATE4 and using the Pantheon theme. It's not the same experience as Elementary, but has many similar design elements. Alternatively, if you need something that is incredibly light-weight, Bodhi Linux has become my favourite go-to for older hardware. It will run on just about anything manufactured since Y2K, including machines with graphics cards that have 128MB RAM.
1 The MacBook Pro (2,2) technically had a maximum memory limit of 3GB. However, you could get it to almost 4GB with a bit of work.
2 The link I had with the source of this number seems to have died at some point in the last year. However, based on experience supporting people coming to Linux with older hardware, 384MB is certainly the minimum you'll need for the graphics device. Dedicating more will only improve what you see on the screen.
3 The MacBook Pro (2,2) shipped with a SATAII interface, which limits transfer speeds to 300MB/sec. Any SSD manufactured after 2009 should be able to provide this amount of throughput.
4 Pronounced mah-tay.