IONOS and SSL certificate issue

I have domain purchased on IONOS and they have one horrible practice. They blocked (only for main) domain LE SSL authorisation and there is no option to remove it by IONOS. So, we have two options and I would like to have some guidance about both (if it is possible) for case to use it on cloud computing with OLS web server.

1) FIRST OPTION - A certbot plugin for enabling DNS authentication with IONOS

So, is it any way that somebody post EXACT steps for OLS (on page is quite clear example for ordinary server settings)?

2) SECOND OPTION - Using IONOS issued certificate
It is (for me) confusing as it is ordinary private key and IONOS published tutorial for PLESK (, but (for me) is not clear how to use it on OLS Console Listener section (as that is obviously all to be done - I think).

So, some explanation will help.