Add ISPConfig to already existing webserver (Import Configuration from NGINX)

Just installed ISPConfig on our webserver that's been running for a year now to make it easier for my colleagues to administer the server.

Any possibility to import previously existing NGINX, MySQL and Jailkit Configurations into ISPConfig so websites show up there?

Also, ISPConfig seems to be tailored more towards actual website providers, given there's a DNS and eMail module. Can that somehow be disabled? I only need the GUI to provide an easy way to administer NGINX websites; so user (SFTP, Jailed SSH, MySQL, ...) and configuration management (what PHP version to use, LetsEncrypt, ...)

Is that something ISPConfig can do or is there an other CP that might be a better fit? Would be truly grateful for any sort of input. BR