So I strongly agree with both your post and @uzirath's. With yours specifically as you touch on Skilled Play which is something I'm concerned with, and with uzirath's regarding the focus of resources.
In BitD (I'm not sure if this is the flashback mechanic or something else), there is the thing...
What @tetrasodium and @Nefermandias rings true.
5e, does not work like some of the older editions, where the monsters on their own could kill, more often than not one requires to homebrew the monsters, create house rules and/or use GM fiat to seriously threaten or kill PCs.
So just to bring it a little back to the OP, one way I use GM notes to assist me is with Skilled Play over the course of the campaign.
Just to be clear I’m not referring to combat strategy or old school dungeoneering when discussing Skilled Play over the course of a campaign. I’m zeroing on...
1. Standard - Forced a high magic setting which I disliked as a DM, fully powered characters all the time
2. Conversion of SR to LR - Didn't solve the above issues
3. Gritty System - Players were frustrated, hurt verisimilitude, pacing issues
4. Die Roll for Recovery of Abilities tied...
Like others have said audio will be your primary concern - which I found was the issue when playing online via discord or other. The table just has to engage more respectfully with one another as opposed to in-person. It is an adjustment and will slow the game down in parts.
Combat visual is...
Sorry, I've been popping in and out of this convo so have not been following as closely - what are the secondary modifiers you are referring to?
And second that Cthulhu book as a little too pricey for me right now.