Wordpress childtheme modification!

I have a classified ads theme that needs to

1. Upgrade to the new version
1. Integrate an html template for a better mobile UI/UI

Looking for someone that experience in wordpress childtheme modification, css/html expert.

The classified ad theme using Vue.js, do not bid if you just know how to design using Elementor and other visual editors, this job will require more than that. If you can design UI/UX is a plus but not required.

All modifications need to be in childtheme!

Thanks!