Prestashop redirects to old domain after changing it in Database

First of all it's great that you follow each step in correct manner. Now the problem is:-

When ever you are running any domain on your browser. Browser create cache and cookie for this. If you change any setting of your domain, it will not reflect till you not clear your browser cache and cookie completely.

So just remove your browser cache and cookie and try to check is it working or not.

Note:- Based on your process that you follow, this only problem seems to exist.

For prestashop 1.7 you have to modify some values in the database:

• ps_configuration table and change PS_SHOP_DOMAIN and PS_SHOP_DOMAIN_SSL to your new domain name, e.g. mydomain.com
• ps_shop_url table and change again ‘domain’, ‘domain_ssl’ fields to your new domain name and ‘physical_uri’. If you copied files into root folder, the path will be simply ‘/’.

More on https://blog.premium-templates.eu/how-to-move-prestashop-from-localhost-to-domain-or-vice-versa

Note: browsers cache redirections, you will have to clean your browser cache. Check https://www.getfilecloud.com/blog/2015/03/tech-tip-how-to-do-hard-refresh-in-browsers/ to know how to do a "hard refresh" for your browser.