migrating from outlook 2016 on windows-10 to outlook-2020 on MacOS. which outlook is accurate?

from pat321gang.

i'm attempting to migrate from outlook 2016 on windows-10 to outlook-2020 on MacOS. which outlook is accurate?

our company uses gmail.

i have 4 sources that I would think would match perfectly but they don't:

1. - www.gmail.com
2. - outlook 2016 on windows-10
3. - outlook 2020 on MacOS with "new outlook" ON
4. - outlook 2020 on MacOS with "new outlook" OFF

after you're reviewed the jpgs/screen-snapshots here...why doesn't the Outlook 2016 on windows 10 matchup (size of inbox;  sent messages, etc) EXACTLY outlook 2020 on MacOS with "new outlook" OFF?

thank you.

patrick