First of all, SRT (Split Render) is intended to work with very high resolutions (8K, 16K, 32K, etc), or with very big projects that a 2GB (for example) graphics card can't process. SRT processes are time consuming. The more splits, the more time will be needed to process them. So try to render with less splits. I've managed to render a 16K image with just 12 splits.

First of all, complex scenes will fill out GPU memory faster than normal scenes. This means that there isn't a preset for everyone, you need to adjust some settings according to your scene. As a reference: Crash before start render (when preparing the render): your GPU can't handle all the data you send to. You need to optimize your project. Crash at first render: Again, too much data. You need to optimize your project. Crash after first renders (during borders or first split renders): your GPU memory is filled (lets say) at 70%-80% before the render. Usually by disabling "Persistent Data" in Performance will be enough to render the scene. If not try to optimize your project just a little. Computer hangup and must be rebooted manually: Disable "Persistent Data" in Performance. Crash above 50%: almost there... Set Splits to a higher value (you can see the crop size in SRT Info panel). Crash at final splits renders: congratulations! Set Splits to a higher value and you are ready to go!

Corrupted file can occur, of course, but before remove that file, try to open it in Composition Editor, in a new Blender file. Check each View Layer, and each pass. If it is ok then the problem may be that your processor and ram can't handle that resolution. Or the final image is 8k or higher, or your computer is a little slow (for whatever reason).

In order to be able to render, SRT needs at least 2 keyframes to process it. You just need to create keyframes with "Add keyframe" button along the timeline, while changing border region size or/and position. Same as any other property, but with "Add keyframe" button.

Hehehe... SRT needs to process all frames information before any render. It is a fast process, which ensures every frame and mask to be where is meant to... When you finish to create keyframes, press "Bake animation" button. The player starts the animation, and when finished, the "Render animated border" button will be enabled.

When baking is started, SRT takes the current Start and End frames to set Image Node properties. Do not change start or end frames after bake is completed. To solve it, in the Image node, set "Frames", "Start Frame" and "Offset" values according to your rendered files (just take a look at your render folder). Or you can re bake again the animation.

SRT automatically detects the size of crop region, and compares it with the size set on Blur Edges option. If the blur size is bigger than the crop size, then SRT ignores the setting. That is perfectly normal, and is not an add-on limitation or bug. You are trying to add a blur size bigger than the image, so the square borders would be visible. To solve it you need to lower Blur Edges value, or set a bigger border region.

Usually the reason is because render region size is almost to the limits of your GPU's capabilities. Less splits means less render times, but in that case maybe is better to select more splits.