Longboard skateboarding seems to me to be an absolutely crazy thing to do! But it also seems like it may have some photo opportunities. There is a group organized near where I live and I have offered my services to the group as a photographer.
Here's an indication of what "longboard skateboarding" looks like:
https://www.youtube.com/watch?v=vSBcrmx4aFw
However, surfing is a lot more sane and even more photogenic. I plan to shoot the Super Girl Surf Pro event in Oceanside (about 20 miles from me) https://supergirlsurfpro.com/
I shot this several years ago and used the Canon 7D with EF 100-400mm Mark-2 lens. The pier is a great vantage point to shoot the surfers. I will try it this year using my Sony A6600 with the Sony 70-350mm lens. I think that combination will be quite sufficient at about 1/3 the weight
Here are a few shots from my previous outing:
I took a tripod for the last shoot but found out that I didn't need it. The IS of the Canon lens and fast shutter speed was more than sufficient. However, I suspect that the combined IBIS and OSS on the Sony gear will be even better...
Another trip I have planned is to see the Los Angeles Chargers vs Dallas Cowboys football game in the new SOFI Stadium in Los Angeles (also in September). Our daughter got these tickets for us as a birthday gift...
I plan to shoot the stadium and the fans rather than try to document the game from the stands. My new Tamron 11-20mm f/2.8 lens on my Sony A6600 should be great for this. The stadium appears to be mind boggling...
https://www.youtube.com/watch?v=kCI2x9FkB6c