I am not sure if this is useful to anyone, but here it goes.
Case: Client's old projects had subtitles created manually using BASIC TEXT TITLE either on FCP or Resolve and needed to be converted into SUBTITLE TRACK in Resolve.Solution:1. Export a CLEAN track with only the TEXT TITLE (File > Export Timeline > choose FCXML 1.5)
2. Go to
https://resolver.tools/subsimple/ and choose FCPXML to SRT and import the exported FCPXML earlier. Click SEND and wait for it to be available for download. Save it to your local drive.
3. Go back to Resolve and choose File > Import > Subtitle... (Select the previous Saved SRT from SubSimple). Your SUBTITLE DATA will be created in the Master Bin.
4. Create an empty SUBTITLE TRACK and drag the newly created SUBTITLE DATA into the SUBTITLE TRACK. Now you have full control over your SUBTITLE TRACK formatting and can be re-exported to SRT or VTT as needed.
It worked for me after a long search for a solution.