WP: Replace Elementor Pro with Free Alternatives + Tweaks

I am looking for an established WordPress freelancer to help me with a few functionality and design changes on my website.

Part 1: Elementor Pro Replacement
My site is currently running on an expired Elementor Pro license. I will not be renewing this license. I need you to safely remove the Pro dependency and replace the Pro features (specifically the header, sticky menu, mobile menu, and contact form) with reliable, free plugin alternatives. You will need to rebuild or adjust these elements to ensure they function perfectly without the Pro license.

Part 2: UI/UX Alterations
(Please note: Additional CSS was previously used to make changes to the site.)
- Header/Menu:** Create a fade or shrinking effect on the logo as users scroll.
- Sticky Menu: Add a solid background effect on the menu upon scrolling (it currently blends into the header and is hard to read).
- Mobile Menu: Fix the mobile menu button (currently unresponsive, likely tied to the Pro license issue).
- Dynamic Tags: The headers are currently using dynamic tags, making them very difficult for me to edit. I would like this undone and replaced with a standard setup so I can easily change text myself in the future.
- Image Optimization: The home page hero image is too large and slowing down page load speeds; please optimize it.
- Contact Form: The form is currently broken. Please replace it with a free alternative (e.g., WPForms, Contact Form 7) and add a "Your request has been submitted" success message.


Part 3: Final Security Diagnostic
My website was recently compromised by a Japanese Keyword/Spam injection. I have already performed the cleanup myself (deleted unauthorized users, removed spam text) and ran diagnostics that came back with a clean bill of health. However, as part of this job, I would like you to run a final diagnostic to flag any underlying issues, broken links, or lingering vulnerabilities I may have missed.