Replacing post author to different attribute on the blog page

Hi, I'm using this theme for my personal site right now and quite satisfied with its look and feel but there's one thing I'd like to make a change. It's the post author showing on the bottom left corner of each blog post on the blog page. As my site is a personal site, there's only one author and I found it's quite meaningless to put post author there on every blog post showing. So as the topic title suggested, I'd like to change it to a different attribute (either post category or post tag) but I'm not sure if there's a way to do it other than editing the PHP template file. (I'm still new to WordPress theme.) If I have to create a child theme in order to do the trick, is there a way to apply a child theme with all the customizations already made from the customizer in the parent theme? It's kind of a pain to set everything over again... FYI, here's my site: https://unerase.in.th/ Thank you, unerase