NTA but here is manual instruction for archiving, with minimal software in mind:
1. Assuming you have yt-dlp, ffmpeg (for FixupM3u8) and membership (9000 JPY or 3000 JPY for JS route)
2. Get the Network Tab ready, enter "fanclub" in filter (so you aren't searching for m3u8 yet).
3. Click the video (you may want to let it play for moment to make sure you will get proper m3u8 later).
4. Search for json that goes like "9999999?fanclubId=9999".
5. Open the json and search for fileURL= in the file. That's your m3u8, so the usual way from here (don't forget about FixupM3u8 or your video will be slightly broken).
Video archive is currently at 97 GB, 56 streams (excluding few game streams and all Radio's).
That's 113 hours 24 min 30 sec - approximately 100 hours of this is gonna be Mai talking so you better be ready.
I've seen like 10% but, you might want to check out Chuppachupsu (2023-01-10), bandaids (2022-09-12) or some (elaborate, couple minutes long, unforgetable) CDs (2022-04-24, 2022-05-28, 2022-06-09, 2022-06-28...).
I'm still pissed that only first few months have 1080p streams and then it's 360p.
The web version of fanclub is shit (no control buttons on radio, nerfed comments, the scrolling...), but if the reward is actually missing, that's a new low.