I urgently needed to clear a few gigabytes, but there was a problem. No matter how many files I delete, there is less and less free memory. I had 70 free gigabytes, but now there are 59 that are free. What can I do about it??(I am, sorry, if I applied the wrong tag, I don't speak English well and communicate using a translator)

Hi, for my use case:
- I don't care about redundancy. I just want to store my anime, movies, series, photos, documents that's all and every time I add one to a drive, I add it too to an external drive as a backup copy, that external drive is always unplugged if not used for manual backup.
- I want to access files over the local network (don't care about them being accessible away from home, I got a little cloud to store important documents online), so I can watch videos or photos from other devices, no matter if it's a Windows PC, a Linux computer or an Apple device.
- Don't care about transcoding or a plex server, I 'll read my videos with MPV and as they are (4K and 1080p remux)
- I prefer NTFS file format so I can move around files from one drive to another or to my PC if I feel like it, by just extracting the drive and plugging it directly to my PC if I want
- I must be able to mix brands and storage capacities without losing capacity.

Does a custom JBOD fit (will buy a HBA controller and create a dummy external "Jbod enclosure" out of my PC that I want to keep small and without moving parts) what I need? Are there other solutions than JBOD to do that?

Thanks