You are almost always allowed to self archive the final version, but you have to share the PDF you generated yourself, not the nicely formatted one from the publisher. And some publishers only allow self-archiving outside repositories like researchgate. But most importantly, Google Scholar and Semantic Scholar would pick up most links from blogs and Arxiv.

Use https://v2.sherpa.ac.uk/romeo/ to check. Also, EU projects in most cases now require open publishing and publishers make exceptions even when OA is forbidden (“self archiving is allowed if mandated by the funding agency”).