Here is a link to a PowerShell script that will filter an SRT file to only show a small set of fields,
Extract absolute altitude (abs_alt) from DJI SRT files
This is written for PowerShell 7 and tested on Windows with an SRT file supplied by...
If you shot a sunny sky, it's an accurate representation of the sky at the time you shot it. That would be OK. The gray area is when you replace the sky in post-processing.