dts (or ac3) to 'flac' can mean two things
dts-->decode to PCM(wav)-->flac (lossless compression + tagging)
dts--> put undecoded data in wav wrapper--> flac (this doesn't shrink the file size, it simply allows tagging)
The second option is doable using 'S/PDIF to WAV' in free Audiomuxer software. It's useful if you would rather keep the file as a bitstream, and let a downstream AVR decode it, while still allowing metadata (tags) to be added to it for display in player software.
Also foobar2000, with the right plugins, can do several of the things in the list up there, with a graphical interface, like converting between lossless formats, and DSD ISO to either DSD or PCM files (or both) , see below.
With foobar (plus DSD plugin) you can perform and monitor conversion of SACD ISO files to PCM. Below is the conversion setting window. The default 'PCM Volume' for conversion in 0dB (i.e., no change in level). This typically results in a peak level that is 'quieter' than the corresponding CD, by as much as -6dB. You can up the level in +1dB increments up to +6dB. As you see you can also adjust the LFE separately (this is an interesting option because SACD LFE mastering can be inconsistent from disc to disc, and the way an AVR treats PCM LFE is not necessarily the way it treats DSD LFE...it is a complex subject.) . Check 'Log overloads' to detect clipping during the conversion.
View attachment 58959
For example, suppose you start at the maximum amplification, +6 PCM Volume, on the hunch that a 0dB PCM Volume will peak at -6dB. Using foobar's View-->Console window to monitor the process you can see in real time (or afterwards) if there has been any clipping. If you see clipping in the Console log, reduce the PCM Volume of the conversion process by 1dB, and proceed again. Repeat as necessary until no clipping errors appear. (No need to check in Audacity, etc).
The DSD--PCM conversion is at 24bits . This is not selectable, though the sample rate is (44, 88,176, 352). The ISO can also be ripped as pure DSD (via the Output Mode selector).
'Preferable Area' btw lets you rip either the Stereo, or the MCH layer alone. Or both , with the default 'None' setting.