Tried to run the sample sites on page speed assessors and here's the results (yep, 3 runs on PSI each):

1: https://cbd-2022.pagemaker.link/
GTMetrix: A, PageSpeed Insights: 80-82-82
2: https://anti-pest.pagemaker.link/
GTMetrix: A, PageSpeed Insights: 76-80-79
3: https://yoga-vd4q.pagemaker.link/
GTMetrix: A, PageSpeed Insights: 89-90-75
4: https://shineon-y19k.pagemaker.link/
GTMetrix: A, PageSpeed Insights: 56-59-50

Question: What's with the Shine On template? Are all ecomm templates like this?

We have tons of Templates for eCommerce available in Pagemaker.
ShineOn is one of the template.