Problem solved!
I used the following command line on my separate computer:
sudo certbot certonly --manual --cert-name translite.com.br -d translite.com.br -d www.translite.com.br --agree-tos --preferred-challenges http --server https://acme-v02.api.letsencrypt.org/directory --register-unsafely-without-email --key-type rsa --rsa-key-size 2048
RSA key type as suggested by @petercooperjr and 2048 key size because I noticed all my previous certs had this lenght.
As usual, certbot gave me these files:
cert.pem
chain.pem
fullchain.pem
privkey.pem
But instead of just handing these files to the hosting provider (site5.com) support staff, I decided to try and do it myself.
On cPanel, under 'SSL/TLS', I found three boxes: "Certificate: (CRT)", "Private Key (KEY)" and "Certificate Authority Bundle: (CABUNDLE)".
I looked up and found out that privkey.pem is actually my KEY, cert.pem is the CRT and chain.pem is the CA-BUNDLE. I opened each pem file in a text editor and copied/pasted into the respective text box (except for the CA-BUNDLE, which was auto-filled and I decided not to mess with it).
Thank you all and specially @petercooperjr for the valuable advice!