@raikko9 You really have to check on your export settings. You export black & white images in 32bit RGB colour format, which just bloats the file size without any change. You have to export the images in 8bit greyscale format. Also consider to reduce resolution down to 3200p or something similar. 6900p sure is strong, but also increases file size by a huge lot, while the extra details are just very little.
I re-exported your images to 8bit greyscale (24bit RGB for the colour pictures) and reduced the resolution down to 3200p. Result: 45MB full size for all 26 images, instead of 300MB.
The colour format doesn't reduce the quality at all, neither do you lose detail. Choosing the correct colour format will not affect the image quality, it only affects file size. So even if you don't reduce the resolution, you can still save ~20-30% size if you export with the right colour format.
@RapidBlast Yo thanks for the input. I never really check my export settings honestly, usually i just click export and be done with it. But, I'll try doing that next time for sure