Strip category base from URL without traffic loss on 2 WordPress sites

Hi everyone, I'm currently working on the SEO for 2 Wordpress-based websites. I'd like to have the category base stripped from the URL. Though, these websites are already scoring well on Google for some keywords, so I don't want any loss of traffic because of 'dead links'. I think a 301 redirect from the old URL to the new URL would be the best, but Im open to suggestions. Both websites have the plugin 'Yoast SEO' installed. I'm aware that this plugin has the 'strip category base from URL' option, but for some reason it's not working; maybe you can get it to work though. Ofcourse, you can also come with your own solution. I can provide the urls for the sites on request. This is a very simple and small project, so please bid accordingly. In addition, please post your previous work. Even when it doesn't necessarily have to do with this project, I'm always looking for people to work on other projects in the future. Please let me know how you would take on this project, your price and the estimated timeframe.