If I understand correctly, you have subtitles on the timeline in the form of separate 'Text+' clips, and you want to either convert this set to a standard subtitle track or output it as an .srt file. This can be done using a script.
We can parse the Text+ content, duration, and timecodes, and then use this data to create an SRT file. I have a complex script for working with different types of text clip, and I have made part of this logic into a separate script to convert Text+ to subtitle.
The script has a simple UI that allows you to select where to save the resulting SRT file and includes a start button.
Once the process is complete, the script automatically imports the resulting subtitle file to the timeline. This is convenient because it allows you to check that the file is correct.
I tested the script on a 90-minute project containing 2,000 Text+ titles, and everything worked correctly. However, after testing it on such long videos, I noticed that the CPU load does not drop, even after the script has finished. It is then necessary to either open a new project or restart Resolve. You mentioned that you have a four-hour project, so it's worth bearing this in mind. I have not experienced such problems with short clips.
Download Text+ to Subtitle scriptYou can use the installation instructions from this topic to install the script:
https://forum.blackmagicdesign.com/viewtopic.php?f=21&t=175315Just a quick note: I'm not a professional programmer and I actively use what is now known as "vibe coding"

. This approach helps me to solve many tasks. Therefore, you should bear in mind that many of the solutions in the code may be inefficient.