Relationship between Multiple Tables with Row level security

Hi Everyone,

I am facing issue with Relationship /Merging /RLS.

Here is my issue  i have some tables with mail ids and some tables with Data  .
i need the RLS  that need to apply  to the reports  along with Relationship of the tables .
i have tables like Maintable , Table A,Table B, TableC, TableD,TableE with interlinked connected but i need main table column  Table E column into my report .Actually i am doing merging with one table linked with another  table it is working fine
Country -->Maintable
State -->Maintable
Maintable-->TableA-->TableB-->TableC--->TableD--->TableE
Please check the screenshot for reference.

Please find this screenshot for reference












Please help me on this  issue .
Is there any way to get that Relationships for Multiple Data sets /Tables along with  Multiple tables RLS  without Merging because when i do merging with all related columns  from one table with another  table it is working fine with less number of rows (less than 1000 rows).
when it come to more rows  refreshing with new data getting issues like Timeout  error  or Memory out of space or VM hangout.

Note  : Output is  to get Report 1 and Report 2 from all the tables 
Thanks in Advance 
Sandeep