Hi @Modus Dev ,
To answer your question:
1)Yes, it is possible to increase list view threshold in SharePoint server as the administrator of Central Administrator, however it is generally not recommended to chang it to avoid performance degradation.
If you still want to do this, please try as follows:
Go to Central Admin>Click Manage Web Applications under Application Management>Select the web application for which you’re adjusting the list view threshold>Select General Settings then Resource Throttling:
2)Although we can index a lookup column to improve performance, using an indexed lookup column to prevent exceeding the List View Threshold doesn't work.
So we suggest you use another type of column as the primary or secondary index.
In addition, please note that there are no more than 12 lookup columns displayed in the list view, which will cause the same threshold issue.
More information for your reference:
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