“When I brought the project to my system, the composition looked significantly darker so much so so that it is unreliable for me to work on.”
Luckily you did tests yourself, so you know from the get-go, that settings on your computer do not match. Each file has an interpret color management plus AE has blend color, legacy colors, etc. all these plus you need the exact same codec versions, gamma calibrated monitor…
plus how you are viewing them back out. Quicktime player preferences could be different too. Use your scopes rather. Do a full render-loop, export/import file, with no color changes, there should be no change in gamma. That way tests for a correct color management setup.
Once you have that nailed down, procede, with care, comparing each new cut to the other computer. Some people test with PNG’s because they have in-file writable gamma protection.