I totally feel your pain with that missing pin, it caught me off guard too when I first got my T7! But dont worry, you can still get amazing wedding photos without spending a fortune. The Godox TT685C II TTL Flash for Canon is absolutely fantastic because it was updated specifically to work with those weird Canon shoes. It fits your budget perfectly and the TTL makes shooting receptions so much easier since you wont have to fiddle with manual settings while everyone is dancing! Check out these tips for the big day:

• Point the flash at the ceiling to get that soft bounce light instead of hitting people directly.
• Pick up some Panasonic Eneloop Pro AA High Capacity Batteries because they keep the recycle time super fast for candid shots. Honestly, you are gonna love the results once you start bouncing the light! Good luck with the practice!

Honestly, it's a bit of a mess with that hot shoe. I've been shooting for a long time and that center pin removal was a total curveball for everyone. Basically, your T7 needs a flash that can talk digitally through the smaller pins because it physically cannot send a simple fire signal through the traditional metal contact point. In my experience, you want gear that just works when things get hectic at a wedding reception. You don't want to be menu diving or worrying about a firmware glitch when the cake is being cut.

• The Canon Speedlite 430EX III-RT External Flash is the gold standard for your situation. It's native, so there is zero guesswork with compatibility. It fits your budget if you look for a clean used one, and the reliability is unmatched. It has full 90 degree tilt and 180 degree swivel which is what you need for those dim ballroom ceilings.
• If you prefer a third-party option with more power, go with the Godox V860III-C TTL Li-ion Speedlite for Canon. I've tried many Godox units and the V-series is much more reliable for events because of the dedicated lithium battery pack. The recycle speeds are basically instant compared to standard AAs, which is huge when you are trying to catch candid moments in a row. Just make sure you avoid anything labeled universal or manual only because they wont fire on that body. You really need a unit with full TTL support. It'll take some practice to get the bounce angles right, but either of these will serve you well way beyond this one wedding.

Just catching up on this thread. I went through this exact same annoyance with a T7 I picked up for some backup work. If you want to keep it simple and stay under that $200 limit, look at the Godox V860III-C TTL Li-ion Flash for Canon. I have been using it for a while now and I am really satisfied with how it handles. The reason I suggest this over the AA-powered ones is the lithium battery. Ngl, skipping the whole AA battery cycle saves so much money and hassle over time. At a wedding, you really dont want to be swapping out batteries in the middle of the first dance or a big moment. This specific Godox fires perfectly on the T7 because it uses the digital pins for timing, so you wont have to worry about that missing center pin at all. It is a total workhorse and the recycle time is almost instant, which is basically what you need for a fast-paced reception. If you can stretch the budget by like twenty bucks, the Godox V1-C Round Head Flash for Canon is also a killer choice. The light falloff is a bit smoother because of the round head, which makes your bounce shots look way more natural. I have had zero complaints using this setup for indoor events. It gives you that full 90 degree tilt and even backwards rotation you need for bouncing light off walls behind you. Just make sure you get some practice in before the Seattle trip so you are comfortable with the menu.