Global Site Tags not working after adding Google Analytics codes to header

Hello:

I have added the google analytics codes via Appearance > Elements and adding a hook to the wp_head and it is set to 'entire site'.

But Google Analytics is not working on all pages, leading to very few traffic being picked up by Analytics. I can see the huge discrepancy based on what is shown by Jetpack's wordpress built in traffic report.

I used GAchecker.com to verify this as well. you can see using the data on this Google Sheet from gachecker.com's csv report that in the last 2 columns, it indicates that a large number of pages' Global Site Tags is not detected.

Here is the link:
https://docs.google.com/spreadsheets/d/1qjy_na65stk6KYd1AqLZkSMi9n0_ng0nkIFtNsc5XHY/edit?usp=sharing

I'm not entirely sure how this is happening or how to fix it, any help would be appreciated!