Hello,
Unfortunately, performance is hard to troubleshoot without more details. Are there any errors in the log file? If you enable the web browser developer tools (F12), do you see any errors? How long does it take to run? I would recommend starting here for some performance monitoring tools:
I hope this helps.
I do believe support is different from buying the professional version, but you would need to contact sales to verify and make sure. I do not know about pricing or anything like that unfortunately.
Regards,
Paul