how to safe blog from google core updates?

I don't think there's a way to make a site completely safe from updates. I'd just focus on useful content and not try to chase every algorithm change.

If traffic drops, check which pages were affected first instead of changing the whole site.

In my experience, sticking to high-quality, helpful content and avoiding over-optimized anchor texts is the best defense against core updates. Google is focusing heavily on user intent now. Have you noticed any major traffic drops in your specific niche recently?

There is no setup that makes a site safe from an update, anyone telling you otherwise is selling something. What you can do is avoid being the obvious target, which mostly means not publishing piles of thin pages just because a tool said the keyword had volume.

The other half is not having google as your only source. The people who get wiped out are the ones with nothing else behind it, no email list, no returning visitors, nobody searching their name. The same drop hurts far less when search is only part of the picture.

Focus on genuinely helpful content, user intent, real experience, clean links, and strong UX.

As is usualy, no fool-proof way to be "safe" from core updates. Suppose even a technically sound, white-hat site can lose traffic because the search results themselves change. That also means it's hard to know exactly what you need to do to keep up with the changes besides making educated guesses. Just make sure your site is genuinely useful, can't go wrong with that.
Stick with the usual stuff everyone parrots like original information/experience, satisfying search intent, good site experience and staying within a clear niche (especially that) are probably better long-term bets than chasing whatever SEO tactic is the flavour of the month. There's a good reason why people keep on repeating those points after all. Anyway, Google itself recommends this sort of people-first approach so there's that.

My blog doesn’t rely on too many backlinks, and it has remained safe through multiple Google updates. Focusing on valuable content and strong internal optimization will make your blog more resilient.

Focus on helpful, original content, strong user experience, genuine expertise, and avoid manipulate SEO tactics or low-quality scaled content.

Make original, genuinely useful content, demonstrate real expertise, maintain solid technical SEO and UX, and avoid spammy links or mass-produced pages. Also drive traffic from communities on social media.