For me to check the Domains (Tagging Server URLs) should I use the sam

For me to check the Domains (Tagging Server URLs) should I use the same url as the sales page?

because we are a platform where spyleiloes.com.br is where the user logs in and uses it

and lp.spyleiloes is our sales page/landing page where we run advertisements

what should be the url that I should point to?

oh, we are using cloudfare

I’m not sure I understand your question correctly.
You can use one subdomain for sGTM and use it for tracking on the main domain and any of its subdomains.
So if you for example use a subdomain for sgtm: sst.example.com
You can use it for tracking on example.com or shop.example.com or anything.something.example.com.
As long as it’s all under your main domain.