[Took time longer when opening file, blurry preview on canvas, can't export]

I was working on 4000*3000 artboard with 300 DPI, at the begining i designing it was fine until i found this issue:

1. Preview was blurry and slow response
2. File took longer when i open and consume lot of ram and cpu (not gpu) when running it
3. Export not working (stuck at "exporting" loading screen")
4. still blurry when i try to copy one by one of the object to new file

Notes:

• I use laptop: 16Gb Ram, Ryzen 7 4000 Series, GTX 1660 with max-q design (6GB)
• I also use to export on workstation PC: intel core i5 13600KF 5.1 ghz, rtx 3080ti 12Gb, 16 GB ddr5 ram
  and the result is same as the points above
• its fine when i create new other file
• i try to export in affinity photo and the result are blurry as seen in artboard preview
• i use some live filter from affinity photo

 

*Blurry and object dont chang or move realtime

 

*CPU and RAM usage (up to 10gb)

*Result when i export in affinity photo

[Blend tool]

in this time, maybe we need a blend tools...