I have seen this on several s6 g920v (verizon) and g920p (sprint). In my experience update or reflash stock rom using odin does not solve the problem. In my case, several, but not all were after water damage.
first step is to boot into recovery and try clear cache partition, that will not delete your photos, and may do the trick.
You could try downloading the stock rom (make sure you get the same version you are on currently such as og7 ok9 etc)
extracting the files from the md5, and using tar-Tool_Odin3-v3.07_by_mkh.mourad to make just the boot.img file into a flashable .md5 file, and flashing that under the bl tab using the newest version of odin. I
I believe it is most likely a hardware problem, Any input greatly appreciated on where to check on the motherboard for physical damage that would cause to s6 to boot loop would be greatly appreciated