High blocking time in a specific store (Help!)

[NK12]

Hello friends, I need some help here.
I have a store with the Warehouse theme, but it is giving 82% performance and 380ms of TBT (total blocking time) in GTmetrix. In another test store, with nothing and with the same theme, it gave only 62ms of TBT and 99% speed along with 99% structure and other very low data. can you help me? I've tried uninstalling some apps, pages I disabled from the site, categories etc, but it didn't download the TBT.

Note: I tested the same theme in another store and it gave a speed of 99%, but when I put the theme in that specific store and I already test it in GTmetrix it only gives 82% speed and this very high TBT.
I don't know how to solve it myself, I hope someone can help me to detect the problem, I will be very happy.

My store: kingstorebrasil.com.br

My store's GTmetrix result:
https://gtmetrix.com/reports/kingstorebrasil.com.br/1WYV8WTP/

GTmetrix from a test store:
https://gtmetrix.com/reports/kingstorebrasilecom.myshopify.com/RCk6fern/

[OneCommerce]

Hello @NK12 ,

We are OneCommerce team and we provide solutions for your e-commerce business.

According to metrics that you provided, some possible causes of high total blocking time (TBT) and a lower performance score could be:

• Unoptimized images: optimize your images to reduce their size.
• Unoptimized theme code: Reduce the number of HTTP requests, optimize the CSS, Javascript files.
• Render-blocking resources: Resources such as CSS and JavaScript that block page rendering can increase TBT.

Hope these information is useful for you, please don't be hesitate to contact us if you need any further support.

If you find our reply is helpful, please hit the Like button or mark it as Accepted Solution to let us know, it encourage us to support more and provide more informations.

Best regards,

OneCommerce team

[NK12]

Hello, friend. I don't think it would be a problem directly with the theme, such as scripts, css or js because these same resources are present in the test I did using the test store, and to test I didn't put any image. I left the theme completely "clean" to test... Complementing the question, I have the same theme (Warehouse) but with several modifications made to its structure and design, and it does not have this gigantic blocking time testing in the same store where the original theme and without modifications has a large TBT.