I'd say code is one of ChatGPTs strongest areas because it's a fact-based thing... If you describe what you want it to do well enough, it will do it. Obviously it will be buggy sometimes but just tell it that and get it to debug the script itself... It'll ask you to add in de-bugging code and then tell you what the output means.
I've made it write me a crypto trading bot, doing stuff I had no clue about before I started that project. It takes alerts from a charting website, sends buy and sell orders to an exchange and logs it all in a database... It's also drawn me some charts and plotted on my buy and sells.
I've also got it to sure up code for injection vulnerabilities etc... You can e.g. paste in some code and say "tell me what's wrong with this code in terms of vulnerabilities, then fix it" and it basically just does it. In terms of graphics and stuff, I don't really know how what packages are best for that but there are plenty of sites that people can use to generate good images that could redesign the site.
Edit: But yes, you absolutely do need to know what's going on behind the scenes code wise, to actually own this site. The hosting company I'm with now is very good... You can give them a problem and they actually fix it / give advice, whereas in the past, if you're on a dedicated server, some hosting companies tended to say it was up to you to maintain the server, unless you paid an extortionate management fee. For $145 a month though, these guys are really good. Also, Vlad did do a lot of work on the site behind the scenes, improving the security / back end. And being on cloudflare (something I did a month or so ago) reduces the risk of DDOS etc significantly.