My rx8 cranks a lot but starts up eventually...... kind of worried me sometimes.
 

I always think that it’s not going to start up and It scares me to death as my DD leading up to winter. How can I fix this to better my anxiety haha

What year is the car?
Does it only do this when the engine is warm?
Is your battery healthy?
Does it crank at low speed (like under 200rpm)?
Have you confirmed your ignition is healthy or replaced it?

2006. It happens every time It starts. Battery is fine. Haven’t tried it with any pedal.....yet. Always it ends up starting after a super long crank so I haven’t tried that.

Then I'd check the ignition components, including the coils, wires and spark plugs. Our OEM coils are known to fail after 20k~30k miles.

+1 and if the starter is turning slowly it will take longer to start. Starters on these cars were upgraded after 2006, I would recommend getting the upgraded 2.0kW starter from a 2009+. They're cheap enough online and will improve starting.
The other reason it could be turning slowly is if the battery has lost a cell and can't provide sufficient current. You wouldn't know that had happened except for the symptoms you're having. I would have it tested.

You may want to post a video or compare to a healthy RX8"s start to gauge if the starter is slow.