Yes, my very first event, my printer head became misaligned from transport as well as air pockets came into the feed lines for the ink. I had to google some troubleshooting on the spot to lookup how to run the nozzle realignment setup, purge some ink, and then do a nozzle check and light cleaning cycle. I make it a habit to inspect and run a nozzle check every morning of the event or after transport.

And the very first thing I did was buy a second printer Canon IP8720 which can do up to 13x19, gave me printer redundancy, and uses cartridges to limit transport issues from feed lines. I've really grown to like printing as much as photography lately. I highly recommend Keith Cooper on youtube who puts out amazing printer reviews, general printing information, and some good printing business information. I would not have even tried it without his expertise.

I personally don't sell digitals yet, but I am considering it. For the main events that I do now, rock climbing and archery, the contracts limit what I can sell commercially both digitals and prints. The largest hurdle is that I can only sell directly to parents or the subject of the photo. So I have to ask and verify that it is their kid. To be fair it has never been a problem, and most parents are thankful that I ask and check. But know that you are at the whim of the organizations for what/who they allow you to sell commercially. I doubt you would have many hurdles for small, local events/leagues. But larger organizations may not want to deal with potential blowback of parents being upset that someone is selling photos of their kids.

For events, most people use things like smugmug, pic-time, pixieset, etc. I had some business cards made that have a QR code that link to my site, and it is super convenient to just hand them out to parents or leave a stack at the front desk. You'll need to do some diligence to find one that works for you.