Regarding what #2 said about "Just go with Yongnuo. Ive been super satisfied..."

• I agree, but be careful. The Yongnuo YN600EX-RT II TTL Speedlite is a great Canon clone under budget, though the battery door is a bit flimsy. You might want to consider the Godox TT685II-C TTL Flash too. It has a much tougher metal quick-lock hot shoe than the older ones, but uses AA batteries. Just make sure to bring extras for a long wedding.

I shoot weddings too and honestly, you do not want your gear failing mid-ceremony. The hot shoe issue with Godox is real, but it was mostly on the older V860II. The newer models are better, but you still have to be careful when bumping into things. Here are a couple of solid options that fit your budget and wont let you down:

• Look for a used Canon Speedlite 600EX-RT Speedlight. The version I is basically indestructible, works perfectly with your 5D Mark IV, and you can easily find them used in mint condition for under $200. I still run two of these and they never skip a beat.
• If you want new, the Godox Ving V860III-C TTL Li-Ion Flash for Canon is actually fine. They upgraded the hot shoe to a quick-release lock which is way sturdier than the old spin-dial. Just make sure to not force it if it feels tight. The lithium battery is a lifesaver for fast recycle times during the reception.
• Another one to consider is the Godox V1-C Round Head Flash for Canon. It is right at your $260 mark. The round head gives a much softer falloff which is great for bouncing off low ceilings in reception halls. Just be careful with third-party flashes on Canon bodies. Sometimes the pins dont align perfectly if the locking lever is not fully engaged, so always double-check your connection before the bride walks down the aisle.

Just go with Yongnuo. Ive been super satisfied using their gear for years.

• reliable triggers
• great build Zero complaints honestly.