I have the identical problem. Recorded a note that is too large, believe I have deleted it, bu Sync still is convinced the file is out there somewhere between my four devices and won't accept that the file is deleted. What I have not tried is to methodically go through every device to be sure the file isn't resident there. And, BTW, I submitted a support ticket and had no response.
Good suggestion for a daily todo list. That practice takes discipline but so does using EN consistently. The trick then, it seems, is to organize notes into a hirarchy that lends itself to identifying time and subjec priority. Since I am new to EN, I will ask for suggestions on note organization strategy sources and threads.