Blog commenting has been an SEO strategy since the first time anyone opened up comments on their site in the first place. ... Therefore, you can leave a blog comment with your link and have that linked indexed by Google, thus counting as a benefit to your SEO.

You can disavow those toxic link with the help of google disavow tool.

Not necessarily things you should change as a result of an algorithm update, but to see algorithm updates as an opportunity to look at whether your site makes it easy for search engines to see what it’s about, amongst other things.

You need to Index your blog URL in google search console. Just go to Google Search Console and submit your link in the sitemap section, your blog will be index instantly.

BERT, which stands for Bidirectional Encoder Representations from Transformers, is a neural network-based technique for natural language processing pre-training. From the following link, you can understand in detail.

https://moz.com/blog/what-is-bert

It is Google's neural network-based technique for natural language processing (NLP) pre-training. BERT stands for Bidirectional Encoder Representations from Transformers.In short, BERT can help computers understand language a bit more like humans do.

Yes, It is good for SEO, but it can not help you in the ranking. If you are targeting other countries with domain Extention then it will help. Like Pinterest, Amazon

Yes, the Link building will be relevant in 2020. It will play a big role in the digital promotion of any business. Link Building built credibility, and help your brand rank higher on search engines. That's why it is vital to make link building a part of your SEO plan in 2020.