PG Admin 4.28 is crashing while viewing 10M row data

Hi Expert,
I am updating 10 Million records using COPY command in a table, the table is updated in a minute, but when I am trying to view all row. PGadmin 4.28 which I am using in chrome is getting crashed. I tried it 4 times and it crashed 3 times. After viewing this 10M row the other queries are very running slow.
is there any process to clear the buffer in PGAdmin or process through which the quey in PGAdmin runs at its normal speed?
Please guide me on how to fix this issue.
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