How to find out tables that are frequently read/ write?

Apologize first because I am not familiar with database. So I probably did not find the right doc before posting my question.

I received a chart which is plotted by X - date, and Y - throughput (M/ sec). It shows that recently (after N Jan) the read/ write throughput was increased drastically.

So I lookup on the internet, finding doc like [1] points out that some pg_XXXXX tables, such as pg_stat_user_tables, looks like can be used to check such stats. For instance,

SELECT schemaname, relname, idx_tup_fetch + seq_tup_read as total_read
FROM pg_stat_user_tables
WHERE idx_tup_fetch is not NULL and idx_tup_fetch + seq_tup_read != 0
ORDER BY total_read desc
LIMIT 10;

Is this a correct way to find tables frequently being read? If not what's a better way to achieve this? And how about write? Or any other docs that I should read as well?

I appreciate any suggestions, thanks.

[1]. https://www.postgresql.org/docs/current/monitoring-stats.html