Error 503 on Wordpress+WooCommerce+Woodmart. Attempt #2

Hello! The site https://surl.li/xmmxwn periodically issues 503 errors or Error Establishing a Database Connection. According to the technical support of the hosting provider (Hostik), this occurs due to "overloading the hosting with the site," exhausting their limits.

The site had been working stably for years, gradually growing larger, with high loading speed. In the last few months, a 503 error began to occur during plugin updates or when adding products (in manual mode). However, the speed remained high.

We turned to a freelancer. He helped, but with nuances. The 503 error disappeared, but the loading speed noticeably dropped and bugs appeared from time to time. For example: access was closed to all bots, which caused Google Shopping ads to stop working, and some interface elements disappeared. We tolerated this for a month. In the last few days, the site's loading speed reached rock bottom, and in the admin panel, when adding products, "server lost connection" keeps popping up, and the 503 error started to return. We contacted the hosting, they optimized something, and the site crashed after 10 minutes. They searched for the cause vigorously, blaming Google and Bing bots, but each time their response was different.

Task

1) Find and eliminate the causes of such errors

2) Restore the site's operational speed

3) Compromises in the form of reduced speed, bugs, or mistakes are not acceptable

Requirements for candidates

1) Do the job properly!

2) Work with an understanding of the consequences of decisions made

3) Have experience! The site is commercial, stable operation is important

4) If after completion and payment it is necessary to write about the problem every 3 days, and even if it is being resolved — this is not a global solution, in such a case there will be a request for a refund!

5) Communication via TG

6) After payment, please support the site for at least three weeks. From our side, only plugin updates, manual product additions, and weekly price updates via file.