Enhance WordPress Site Performance & Responsive Design

WordPress experience required. The site is currently offline (taken off hosting intentionally) — all work is done locally on a copy I'll send you (files + DB dump). Deploy via LocalWP, XAMPP, MAMP or Docker, your choice.
Reference / site materials:

Local deployment + README — spin up the site locally, document how to do it in 15 min. Accepted: another person follows it without questions.
Child theme — set up, move all custom edits into it. Accepted: parent theme update doesn't break the site.
Speed — caching, WebP, lazy-load, minification. Accepted: PageSpeed ≥ 85 mobile, ≥ 90 desktop.
Responsive — check and fix at 375 / 768 / 1440 px. Accepted: before/after screenshots.
Plugin audit — remove duplicates/unused, update the rest. Accepted: report as a table.
Backups — configure UpdraftPlus + restore instructions. Accepted: test restore works.
Contact form — validation, spam protection, emails delivered. Accepted: test submission arrives.

Deliverables: updated archive (DB + files), README, plugin table, restore guide, screenshots.
Terms

Bid on the full bundle or individual tasks — specify which
Payment by milestone
State your timeline and rate
Do not publish the site copy or share project materials