The loading time of the website is pretty much dependent on the CMS it is built on. Factors like heavy codes, heavy images, or too much content may slow down the loading time of any website. Now coming to the second question about hacking, any website can be hacked if proper security measures are not followed. Due to the developer's negligence in coding any site can be hacked. You must hire WordPress developer who has experience in developing secure websites, to ensure best practices are followed in your website’s development.