hotkeys for blend settings? (overdrop, alpha under, cross, etc)? I'm looking specifically at the vse for this (if there are ones for the 3d viewport let me know tho). But is there a way to bind hotkeys for the "blend settings" found at the top section of any selected strip?

I know once you click on the blend settings and it displays them all (overdrop, multiply, add...etc..) you can type a key like "o" and overdrop automatically applies ( I cannot find a list of these anywhere either....so that would be appreciated as well if anyone finds one).

This is great, just the act of clicking the blend settings to begin with defeats the point to a large degree. I looked through the sequencer hotkeys list and of course nothing like this is listed there. Generally they are listed in some obscure place under some obscure name. So I'm wondering if they do exist and what these obscure places/names are.

Ideally I just want to click a key in the vse viewport or options (n) menu and have it automatically apply stuff like overdrop to the strip highlighted etc.

If there are hotkeys for effect strips as well that would be good to know (transform, speed control etc). Like I love the hotkeys for viewport changing shift+f1 etc, and rebinded those to f1/f2/f3, those were a godsend.
See this answer for how to create custom shortcuts. You can also use this method for looking up obsure keyboard shortcuts.

For performing transform operations on strips in the VSE, I recommend my fork of the VSE_Transform_Tools addon. For a lot of extra functions for the timeline area, I recommend the Blender Power Sequencer addon by GDquest.