Will constant updates destroy my SERP?

Hi,

TL;DR - will (constant) updates in "ultimate guide" blog/post destroy my SERP? Should sites/posts be "static" to get best SERP results or is it okay to update them after they are already released?

I have prepared my SEO strategy around the idea to create
1. "1 x home page" (around main topic/KW)
2. "1 x blog/post ultimate guide" that contains all pieces of the main topic, KW. Goal is to rankas high as possible and then send visitors to my main service site (home page)
3. "multiple blog/posts" that contains sub-KWs around main topic. Goal to rank for this particular sub KWs as high as possible
4. Other irrelevant pages

For now it looks like my ultimate guideline might need updates (not sure if those updates will be on constant basis, but I might add additional text, new findings, pics, etc.) so I start to worry if each update will affect my SERP. Should my posts like ultimate guideline be static or I can update them? For example in my worst case scenario my "ultimate guideline post" start to rank, then I upadate it and I am again at the begining - any comments? What solution do you propose?

Thanks!