Like someone mentioned, you gotta be careful with compatibility. I once bought a generic flash that fried my hotshoe... scary stuff. TL;DR: Get Yongnuo YN685 II Flash for Canon for reliable, safe TTL.

TL;DR: Since your T7 lacks the center sync pin, you need a TTL-enabled flash like the Godox TT685IIC TTL Flash for Canon or the Godox TT350C Mini TTL Flash for Canon to make it fire. Basically, those $50 generic ones usually rely on that middle pin to tell the flash when to pop. Without it, they just sit there... super frustrating. I dealt with this exact issue when a buddy got a T7 and none of his gear worked. For a wedding, you definitely want E-TTL anyway because the lighting changes fast. The Godox TT350C Mini TTL Speedlite for Canon is right around $85. Its compact and reliable, though it uses AA batteries. If you can squeeze out a bit more cash, the Godox TT685IIC Flash for Canon has more power for fighting harsh sunlight. Both use the electronic pins to communicate, so they work with your specific hot shoe.

i’ve spent a lot of time looking at the voltage and trigger specs for these rebel bodies and i’d actually politely disagree with the suggestion for the smaller godox units for a wedding. while the tt350c is a decent budget pick it only has a guide number of 36m which is kinda weak when you’re fighting the sun in a backyard. basically you’ll be running it at full power every single shot and the recycle time will be like four seconds or more which is way too slow for a fast-paced ceremony. honestly i’ve been very satisfied with the Yongnuo YN568EX III Speedlite for Canon which usually stays right around $90 online. it has a much higher guide number of 58m and works well with the t7 electronics despite that missing center pin issue because they updated the firmware specifically for it. it’s a more methodical choice for your specific power needs and i have no complaints on the light consistency. quick tip tho... definitely check that your flash is set to high speed sync mode for those outdoor shots. since the sun is gonna be behind them you’re gonna need a very fast shutter speed to keep the sky from turning completely white and hss is the only way the flash will fire correctly at those higher speeds. it’s a technical detail that a lot of people miss until they get to the venue and realize their photos are totally overexposed because they're stuck at 1/200th of a second. having that extra power from a full-sized speedlite makes a massive difference when you're literally competing with the sun.