Magento 2 issues - ajax 404 and indexing problem with two sites

Do you thrive on tackling intricate eCommerce challenges? We're seeking a highly skilled Magento 2 developer to diagnose and resolve two critical issues impacting our store's functionality.

The Challenge:

Issue 1: Defective Configurable Product Swatch Functionality

Clicking a configurable product swatch on the catalog page results in a blank product image instead of an updated photo, as expected.
Browser console reveals a 404 AJAX error.
Importantly, this issue is isolated to the catalog page and does not occur on the individual product page.

Issue 2: Conflicting Reindexing Between Separate Magento Installations

We maintain two independent Magento 2 installations on the same server with distinct databases.
A critical problem arises when reindexing one site: products mysteriously disappear from the catalog of the other site, and vice versa.

Your Role:

You'll meticulously investigate the root cause of both issues using your in-depth knowledge of Magento 2 architecture and debugging techniques.
Develop and implement a robust solution to ensure proper configurable product swatch functionality on the catalog page, eliminating the 404 error.
Formulate a sustainable strategy to address the reindexing conflict, guaranteeing seamless reindexing for each Magento installation without impacting the other.
Maintain clear and concise documentation throughout the troubleshooting and resolution process.

The Ideal Candidate:

Proven experience as a Magento 2 developer (2+ years) with a solid understanding of core functionalities and best practices.
A keen eye for detail and a methodical approach to problem-solving.
Proficiency in PHP, MySQL, and debugging tools.
Excellent communication and collaboration skills.