Thanks:
I’ve had 502 and 503 errors for a long time. in the end, according to your advice, I hired an speed optimization expert to make my website loading facter. After his page loadtime optimization several things went wrong and I can’t even get that expert back because the payment has already been paid.
1- Organic traffic almost half.
2- Bounce rate still increased while website loads quickly.
3- In google search most of my products don’t have correct meta discriptions anymore.
4- Products ranking has gone all the way from 1-2 page to 4-5 page.
5- DR from my website also came down
6- Sitemap_index.xml works in search console but not redirecting from http, www to https.
In this hopelessness, I request you please take a look as a senior theme author perhaps you can find easily one of the cause which went wrong.
**That expert installed his own cache plugin and put some php coding in child theme function php folder too.