How to change search engine in new tab search box

[HastaLuego]

Greetings! In the current version of the browser, Google search is not among the search engines in the search bar on the New tab page, and you can't add Google to it yourself in any way. For Google, use the address bar search.

Hi, то бишь привет! I have one question and 2 bugs.
1st How to change default engine to Yandex.
2nt I have a local storage value sized 700k, but when I try to save it wth following API

x4.onclick= function(event){
    x4.href ='data:text/csv;charset=utf-8,' + localStorage.test;
    x4.download =  'Test-' + new Date().getTime().toString() + '.txt';
      };
where x4 is an 'a' element (link)

I've got only 300 k file, the rest is cutted off
No problems with older versions of Cent or the other browsers, where I've got a fullsize file.

3rd CORS issue, startin with flags --disable-web-security --ignore-certificate-errors  --allow-running-insecure-content,
nonetheless I'm getting the followiing error has been blocked by CORS policy: No 'Access-Control-Allow-Origin'.

Sometimes it blocks, sometimes it doesn't.