MIHA - Cloverleaf Event

I can't get over this is called a Cloverleaf event.  It's Barrel racing.  But my knowledge of anything horse sports related is quite limited.  But I know more now than I did a year ago.  
When it is drawn out, I see the cloverleaf.  But when I look up, I see the barrels.
What ever, it is fun to watch.
My goal for the day was more about shooting with different settings.  The event was in an arena with questionable lighting at best.  To start, I had no idea for what speed to use.  For the Cloverleaf event, I was guessing over 1/320.  For the increase in speed, I was giving up ISO.  And I wasn't going to use a flash,
In the end, 1/500 worked well.  I could get by with 1/400 if I had too.  I also settled in on f/5.6 to start.  I'd also start, with the D500, at ISO 8000.  Less is clearly better in the ISO department.  What I'm finding out is that with the higher ISO, the image size is limited.  They are fine on the phone and tablet, and OK on the monitor but I think a large print is out of the question.  For a large print, a flash would be required.
Again, this issue is only with shooting in the arena.  Outdoors in the sunshine, no issues.
The point of all this is that I don't have many photos that are really 'good'.  Most images are dark - but somewhat savable.  Thank you RAW.  Most are really noisy - but somewhat savable.  Thank you Topaz DeNoise.
Most of the shots look alike.  There were only two good shooting vantage points, and I logged time at both.  Also, because I'm new at this, I was fairly fixated on certain points in the event.  So, a lot of the shots look alike.  That's OK, lots of room for improvement.

I like this first shot because for me to get the banner in, I couldn't go in real tight.  To me, the banner helps center the shot.  The subject team did their part.

The first two are ISO 10000 and the last one is ISO 12800.  Good on the small screen.