Reliable CA Intermediate Certificates ( is it compulsory of not? ) HSNM administration backend general discussion

[Karwan]

Dear Gents,
I created my CRT file and Key in the SSL Certificate tab. As shown in the pictures, I sent both files to the company to create a wildcard certificate for me.
So, could anyone help answer my questions to be clearer, please?
Q1: If I upload only Key file and CSR File, would it be secure enough?
Q2: Are (Reliable CA intermediate Certificates) compulsory to be uploaded, and should we buy it as well?
Q3: Why do we need (Reliable CA intermediate Certificates)? Does it add one more layer of security?
Q4: I got 3 files back for the AC reseller but do not know when we need the newcert file and when it should be used.
Q5: If a device requires certificate upload manually, which files should be uploaded to the gateway?
Q6: When I tried to buy Wildcard Cert, the company asked me to send them CSR and Key files. Should they get both files or only the CSR file to create the CA for our domain?

[HSNMSupport]

Hi,
Q1) No, you need at least KEY + CRT.
Q2) No, it is not mandatory. You must upload to ensure 100% compatibility with all devices if they do not know your Certificate Authority (AKA Ca).
Q3) same as Q2
Q4) Ask them, basically we do need KEY + CRT in separate files
Q5) It depends on the gw provider. We have a dedicated guide for all Vendors compatible with HTTPS and SSL upload.
Q6) We do not create Keys. Send them the CSR ( Certificate Signing Request ) and ask them to provide even KEY file within certs.
S.T.