taemex import my HTML backup bookmarks
Sorry, you'll have to do it manually. I'm not aware of an import feature yet.
taemex How to enable permanent Incognito Mode?
In settings > privacy and security there is an option for open external links in incognito, and you can replace the normal icon on your home page with one that opens into incognito
taemex How to add BRAVE as a Search Engine and set it as my only search engine?
First go to brave search webpage and search for something, then once you've used it at least once it will appear in the list of search engines that you can set as default and run from the address bar