I finally got around to performing a drain / fill on my 2019 ST. Rather than recap everything said, I'll post the numbers and results.   Fluid out: 5 qt 24 oz Fluid in (net): 7 qt 9 oz   Notes: The net amount accounts for the spillage (6 oz) while leveling the fluid using the sight plug Fluid in includes the additional quart added after leveling the fluid and installing the sight plug Slightly elevating the passenger side with a jack while draining helps the fluid drain more quickly / completely Leveling was done with the fluid at 185 F while parked in my garage  I was 1/2 qt low even before taking into account the additional quart added after leveling. Most of the lazy shifts and slow engagement is gone. There is still the occasional oddity, but these are now the exception and not the norm. I'll probably reset the adaptive learning again when I have time to properly perform the post reset procedure. Hopefully this was also the cause of the few egregiously slow engagements from a stop, but time will tell.

I hope it's just the battery getting old.. 3 years is not a long time for a quality battery, but if you were using the auto stop/start system, then it does make some sense that the battery would be tired if it did a lot of cycles.  FWIW I also had the H7 installed but I traded that vehicle in and don't have pictures I don't think

I think I will have to go with an H7 battery. My current battery is about 3 years old. The auto start stop hasn’t worked for about 10 months. The radio doesn’t stay on after the engine turns off. I always get the system off to save power message. When I start the car I have to wait a little while for the screen to turn on. Fordpass only stays connected for about an hour. The keyless entry stopped working. The biggest problem is not being able to use Fordpass to remote start, because it’s getting cold out. 

@onyxbflyDo you have any photos of the H7 battery installed?

My wife and I just purchased a 2022 Edge Titanium three weeks ago. It’s used obviously, but only one owner and 33,xxx miles. It’s a great car, but I noticed on the way home from the dealership that the back bumber was moving quite a bit. I did some research, and here I am! I’ve tried to find the part(ours has the towing hitch), and it is no longer available. Do you have any idea where else I could find it? The Ford price isn’t too bad at all, so I’d like to find something close in price.   Thanks,   Jason

As @Cerberus stated, H7 is probably overkill, by a big margin. As for fit, I don't expect it to fit. I remeber the battery tray having 3 holes for mounting thr battery, for H5, H6 & H7.

onyxbfly   has the H7 installed, so ask him for photos of the installation and that will give you a good idea of the available space to accommodate the H8.  

Not 100% sure but I suspect H7 is the largest, and more than the vehicle really needs unless you have auto start stop enabled (which i vehemently advise against) 

Is H7 the maximum size that will fit or has anyone tried to install a H8 battery?

Thanks, I'll do that even though that still means replacing the unit for me. I hope you're right. One of my biggest concerns is what if it's a cracked wire in the harness not the unit it's self.