No sure if it’s possible, or if it’s a lot of work, so do not spend time for this if it’s not interesting.
I suggest to add the 38 blend modes of GIMP, to group them (or the one already in), and to be able to use them with “keyframe”:
Dissolve
Color erase
Erase
Merge
Split
Lighten only
Luma/Luminance lighten only
Screen
Dodge
Addition
Darken only
Luma/Luminance darken only
Multiply
Burn
Linear burn
Overlay
Soft light
Hard light
Vivid light
Pin light
Linear light
Hard mix
Difference
Exclusion
Subtract
Grain extract
Grain merge
Divide
HSV Hue
HSV Saturation
HSL Color
HSV Value
LCh Hue
LCh Chroma
LCh Color
LCh Lightness
Luminance
I did found some math of those blend modes if it can help/
This is not really possible without rewriting the effect to not use Qt, which we just switched to gain support for 10-bit video. Our focus is on quality and performance now rather than counting how many things can be included. There are so many factors to consider now when adding something because it requires maintenance: CPU parallelism, GPU, RGB or Y’CbCr, 8 or more bits per pixel. See how today not everything is available in all of these modalities.
There is no such thing as keyframes for blend modes because they have no parameters. You need a parameter in order to control it over time. If you want to change modes over time, then use the Blend Mode filter and filter trimming. Maybe you want to keyframe the Opacity filter instead.