Spamming content / product pages spam on new ecom website

Hey, my question is simple yet I don't find anything related to this on the web :

If I start a new ecommerce website and upload 10k + product pages on it, will I get seen as spam ?
I've already done a few tests here's what I know at the moment :

1 site launched on new domain name / I added 1800 product pages with unique titles and descriptions on each : google indexed 1200 pages in 24 hours and it got it's first top 100 keyword in 24h too
1 other site with 6 months of age + 100 nice RD + 5k traffic + 600 already existing product pages => i added 1200 products on it instantly : they got indexed in 2 days and it seems like it boosted the site's rankings / I got visitors from these new pages in a matter of days

But, a friend of mine launched a new site on a new domain and added 7k+ products instantly and 1 month later he has only 130 pages indexed / 33 keyword in top 100

So I'm wondering, is there a content spam detector on google that I should be aware of ?

Thanks for your time and feedback !

Google works in a mysterious way, What might not work for others might work for you