Gapless playback of FLAC files.

All I want is to send gapless FLAC to my dac

Are you sure? If YES, then how does it matter that it is sent via a computer Vs a transport? How are you sending these FLAC files to the DAC, if not using a computer?

I am now sending the files with the Blu-ray and spdif cable. I wanted to do it without a computer because I wanted to leave the computer free for other things and I can't send 24/192 or dsd files over usb. The audio sounds quite good from the Blu-ray player, except for a gap in gapless files.

My Panasonic 9000 says it does gapless playback, but also notes that some differences in the files that are supposed to be continuous may cause issues. I have never tried the gapless playback but now have a reason to :-) Using a dedicated device other than your regular computer to play files is always better. I find all kinds of artifacts that show up audibly when my computers are feeding the content to my DACs. Mostly gaps where something happens in the computer that must have a much higher priority that it affects the file output. Not probably a big deal for kids listening to MP3 files on a cheap powered speaker, but a deal-breaker for using computers with a high end system and critical listening.

During the pandemic I got JRiver and played with all types "renderers". DVD players, Blueray players, Sonos speakers TVs etc. With JRiver I can see a variety of details at the renderer level which is key. A very large amount of my music is gapless.

My results are simply that the regular DVD/Blueray players are quite unreliable in this regard with none being solid. I even did the same with a relatively new Sansung TV and while no gapless but it also resampled everything to 16 bit no matter. One TV actually reversed the channels when uses as a renderer. 

So despite what should be a super simple job to achieve I purchased a real audio streamer which of course does gapless and other things they way they should be done for an audio user. 

What are you hoping to gain with gapless playback? I intentionally set my streamer to add 3 second delay to allow my DAC to adjust between resolutions.