yo, oh man, I totally feel u on this. I actually used to shoot indoor events with the Canon EOS 90D and I've spent way too much time testing these! At first, I was a Canon purist, but then I did a huge gala and realized swapping AA batteries mid-shot is literally the worst. For your situation, here's what I recommend:

• Get the Godox V1-C Flash for Canon. It has 76Ws power and the round head gives a reallyyy smooth light falloff.
• The lithium battery is a total beast. It recycles in about 1.5s at full power, which is huge for fast-paced events.
• It handles E-TTL and HSS perfectly on ur 90D sensor. Basically, while the Canon Speedlite 430EX III-RT has a better red AF assist beam, the convenience of the V1 wins every time and u dont need AAs. I switched and lowkey love it. gl! peace

tbh i've shot plenty of events with the 90D and the Godox V1-C Flash for Canon is definitely the winner. That round head gives a way smoother falloff. If you want better value tho, the Godox V860III-C Flash for Canon is basically the same tech for less cash. The lithium battery literally lasts all night and the AF assist works perfectly with the 90D's focus points. gl!

just saw this and had to jump in because ive spent way too many years testing recycle times and thermal cutoffs. quick question for you tho... are these events usually in big halls with high ceilings where you need to bounce light from 20 feet away, or are you doing more tight candid shots? it makes a huge difference for the power draw. honestly i think people sleep on brands like nissin when they only look at godox or canon. over the years ive found that while godox is great for the price, their AF assist beam can be a bit wonky with the dual pixel AF on the 90D. check these out:

• Nissin MG80 Pro for Canon is probably the most reliable thing you can put on that hot shoe. it uses a quartz flash tube so it basically wont overheat even if youre firing rapid bursts for an hour straight. plus it takes li-ion or aa batteries which is super handy.
• Profoto A10 AirTTL for Canon is the gold standard if you want perfect color consistency. it costs a limb but the interface is so much faster than digging through menus mid-shoot. in my experience the canon 430ex is a bit underpowered for big indoor venues. if you want that pro level reliability without the godox quirks those two are your best bets.

In my experience, grab the Godox TT685II-C Flash for Canon for $130. Its AF assist and HSS work perfectly on the 90D without the massive price tag of the others!!

ngl im literally in the same boat as you right now. Ive been scouring forums for like three weeks trying to find a flash that wont flake out on my 90D during a long shoot and it is driving me crazy... reliability is basically my top priority since im terrified of a flash dying mid-event but it feels like every review says something different about the AF assist accuracy. Honestly its so frustrating because I am ready to buy something today but i am still just as confused as when I started searching!