Redesign a website

Depending on deadline and your knowledge on how coding and designing web site, perhaps that going from a CMS (wordpress - https://wordpress.org/) based on a template (themeforest - https://themeforest.net/category/wordpress) could be an easiest and fgast way to go.

See my reply to this related discussion.

https://community.adobe.com/t5/dreamweaver/designing-adaptive-websites-for-multiple-devices-android-ios-mobile-tablet-rotaions-ec/m-p/11467126?page=1#M205814

Almost every website becomes a mess over time, even the ones I work on exclusively myself. You add a bit here and there, some inline css styles for ease and speed etc, when they should be in stylesheets etc, add a lot of page specific php, which is only good for one update, then don't bother or forget to remove it, and adds some more, etc. Yes, the only time a website is NOT a complete mess is when it was first officially released, then its all down hill after that, the more changes the messier they get.

You are correct, steer clear of using tables. Tables are NOT appropriate to use for constructing a website these days as websites need to adapt to all kinds of devices, from desktop to mobile and beyond. I cant give you any specific advice because I dont know the extent of your abilities. I prefer to steer clear of templates and frameworks such as Bootstrap etc but IF youre not a very good designer or coder then you can be forgiven for using such workflows and may well need to use them.