Hi @Imran Nawaz,
Each Search service application has its own search topology. If you create more than one Search service application in a farm, we recommend that you allocate dedicated servers for the search topology of each Search service application. Deploying several Search service applications to the same servers will significantly increase the resource requirements (CPU and memory) on those servers.
When building the search architecture, you should take into account considerations such as high availability and fault tolerance, the volume of your content and the estimated amount of page views and queries per second.
Multiple SharePoint Search Service Applications can be deployed on the same farm, because you can assign search components and databases to separate servers. The recommended limit of 20 is less than the maximum limit for all service applications in a farm.
You could refer to following steps to create second Search Service
If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.