You requested a NM in my queue but I will quote from my rules:
"If your map has big problems/is not rankable in its current state I will try to give you general advice but not mod in detail as that would get out of hand really quickly"
I will be frank, this mapset will need a lot of work until it is in shape for ranking but it's not impossible. As promised I will try to give you general advise on how to improve this mapset as well as your mapping style.
The main issue with the set cannot broken down to just one point as several things attribute to the flow and playability being suboptimal. The easiest way for you to actually find these issues is by repeatedly playtesting your map and looking for spots that feel off or don't flow as well. Then compare it with good ranked maps for inspiration on how else these could be mapped or improved and try to incorporate that into your own mapping style.
Try to use more consistent spacing in breaks and patterns to improve the flow of a map and use less doubles and 4 note patterns as those tend to interrupt the flow if used too frequently or where the music does not require them.
If used too frequently especially on the lower difficulties notes on the red (or even blue) ticks can also impact a map negatively. Try to keep your focus and main beat on the white ticks if you are still new to mapping.
These issues are most apparent in the Oni, where inconsitent spacing and focus on upbeat ticks make for bad flow and playability.
If possible always try to go for background images with a resolution of 1366x768 for optimal quality
Use red (uninherited) timing points only when you want to change the actual timing (like if the BPM of the song changes). For all other timing points (kiai time, SV or volume changes) use green (inherited) timing points.
Keep working on your mapping and don't be afraid to borrow ideas from other mappers and look at how ranked maps achieve their flow. With practice you will get better and might even get a ranked mapset in the future. I hope this advice was at least a bit helpful, good luck.