well if you intended to deckout with this deck having more than 30 cards is indeed important
for a more specialized deckout deck, skull shield and aflatoxin will be your tools to lock your opponent, while at the same time you may "lock" your field with malignant cells too, just to have enormous amounts of healing with the bonds to assure you dont die. It would still have some flaws though
EDIT: ok i read your post again and now i think i know why you are not being able to get good results: you need to choose
It means your deck was built for many situations, his strategy is too scattered instead of focused, making it lose effectiviness
considering the cards you have here, you can either go full lockdown with malignant cells, a deck that triggers death effects for your vultures, or a simple mono-life rush with healing for a chance of EM