Show us your setup: full Ae interface with the layer selected type UU so we can see modified properties and zoom out all the way in the timeline panel.
as you can see i have 20x on the start of the video and 70x
at the end, i'm not sure what these settings mean to be honest, maybe how fast a circle is finished?
although it spins until the end of the video with these settings, but i wanted to make it faster
but if i make it faster it stops in 20-30 minutes.
You're choosing a horribly and inefficient way to do this project. I don't know how many layers are in your composition but if I wanted to loop a rotation of a layer for many minutes or hours I would create a comp that was just long enough for one rotation -1 frame. What say you wanted it to take 30 seconds or one rotation. Create a comp that is one frame short of 30 seconds, add your layer, set a key frame and frame zero of 0° then moved to 30 seconds and set a key frame to 360°. This puts the last keyframe one train past the end of the comp which is what you need to do to set up a seamless loop. Then I would render this file and tell it to loop 50 or 100 times for however many times you needed it to and do the composite in premiere Pro or it will render faster and you can see a real-time preview instantly or if you insist on keeping a 30 minute (an insanely long project for AE) you could get able time remapping and use loopOut() for your expression. You could even just set key frames for one rotation and used loopOut(). Rendering the one rotation loop is going to be faster and more efficient for your final render than any other method. Using the time times 30 method is going to generate a huge number that may cause problems and it forces a calculation every frame which takes longer to render.
Sorry you had all this trouble! Tell me, though...did any of these expert answers help solve your issue? If not, I'd be glad to escalate your case. If so, please let us know what helped you so that you may help others and our experts can benefit from hearing about your experience. Thanks for any feedback you can give!