Search through indexed pdf's slow

I currently use for my Joomla 3 website JiFile for endexing and searching through pdf files such as Newspapers. Unfortunately it seems that there will not be a Joomla 4 JiFile.version.
Hence I searched for an alternative and bought Edocman Pdf indexer. It works, but very slow. In JiFile any search was executed within a second, where Pdf indexer takes many seconds.
Do you have any suggestions?

Hi,
Can you tell me which part of Edocman is slow? Search or indexing documents?
Thanks
Dam

Good morning,

The indexing of 3349 documents took quite a while, but visitors are not effected. Searching the more.
Searching for a single word may take up to a minute, which is just unbearable.

Hi,
Could you please submit ticket on category: Edocman and send me your site url with super admin account. I will figure the cause of issue for you
Thanks
Dam