This is the 2021-2022 Korean historical/romance/sad-ending TV drama series, native title "옷소매 붉은 끝동" ("Red Cuff of the Sleeve"), also known as "Red End of Clothes and Sleeves," "Dress Sleeved Red," "The Red-Stained Sleeve Cuff," and "The Red Sleeve Cuff."

From MyDramaList: https://mydramalist.com/61399-dress-sleeved-red
"In 18th-century Korea, Prince Yi San is a perfectionist haunted by his father's murder. He's set to inherit the throne once his cruel grandfather, the current king, passes away. Despite the emotional scars left by his father's death, Yi San aspires to be a benevolent ruler who reforms the kingdom's laws. At court, he encounters Sung Deok-im, a spirited and intelligent young woman. While Yi San falls in love and proposes she become his concubine, Sung Deok-im grapples with the restrictions and responsibilities that come with royal life. However, as their love deepens, she begins to see the potential to bring positive change to the troubled realm through their union."

IMDB: https://www.imdb.com/title/tt14687200
Wikipedia: https://en.wikipedia.org/wiki/The_Red_Sleeve
AsianWiki: https://asianwiki.com/The_Red_Sleeve

This is the complete set of 17 episodes ranging from 68 to 101 minutes long each. They all have edited "soft" English captions; that is, English subtitles are part of the MKV file and the subtitles can be enabled or disabled as you wish.

I downloaded the source videos named like "The.Red.Sleeve.E01.1080p.H264.AAC.WEB-DL-Phanteam.mkv" and extracted the English subtitles from those. Then I...
- Used Subtitle Edit (by Nikolaj Lynge Olsson) to find and fix all flagged issues
- Watched the series and italicized music lyrics, characters' thoughts, short flashbacks, and some off-screen dialogue; also color-coded some subtitles for clarity as appropriate, using yellow, teal, and salmon colors for signs, flashbacks, and written/printed material respectively
- Added 0.7 second to each subtitle (where possible) to allow more time to read them and adjusted words/minute to at least 280
- "Softened" all subtitled profanity (bastard --> jerk, damn --> darn, bitch --> witch etc.)
- Corrected commonly-found typos, converted many word pairs into common English contractions, brought together sentence fragments, removed unnecessary translated words like "oh" and "ah", etc., converted Korean Won amounts into American Dollars, converted British terms to American ones, and (where needed) converted Korean names to AP style (family name followed by hyphenated given name)
- Split up and/or rewrote lengthy and/or wordy subtitles to maintain 23 characters/second and/or 280 words/minute or less
- Used Handbrake to create new MKV files using my subtitles

Format: MKV
Format info: Audio Video Interleave
Total file sizes: 24.0 GB (25,818 MB)
Total duration: 20 hours, 58 minutes, 48 seconds
Overall bitrate: 2728 Kbps

Video format: MKV
Video Codec: H264 - MPEG-4 AVC (part 10) (avc1)
Video bitrate: 2600 Kbps (2-pass)
Video width: 1920 pixels
Video height: 960 pixels
Video frame rate: 29.976 fps
Video decoded format: Planar 4:2:0 YUV
Video scan type: Progressive

Audio format: MPEG AAC Audio (mp4a)
Audio language: Korean
Audio bitrate mode: Constant
Audio bitrate: 128 Kbps
Audio channel(s): 2
Audio sampling rate: 48 KHz 

Subtitles:  English as soft captions - feel free to rip & use or distribute as you wish