Been several times as well both to Varedero and Cayo Coco. Beaches at Cayo Coco were better but windy as it tidal frontage. You can walk out seemingly forever when tide is out

. It's beautiful. No excursions or activities there, it's an island, but very relaxing !
Varedero has a lot to do tourism wise, many things to go do if you like. The double decker bus goes up and down the strip all day and you can get on and off as you please for $3 roughly!
As for the food, yes, Cuba is limited. The seafood and fresh fruit and vegetables were always plentiful and for me palatable. I have never come home hungry or unwell. Just my experience though.
I found it safe, though I don't venture off the resorts at night. I even traveled to Varedero solo (female, 40's) and had no worries.
I will add, of all the places I've been, Negril Jamaica gets my vote every time. Riu resorts are awesome, the food is outstanding, and the service is great!
Enjoy your trip!