Partitioning options

Hi ,
We have a system which stores customers' transactions. There are a total of
~100K customers currently and the list will increase in future but not
drastically though(maybe ~50K more or so). The number of transactions per
day is ~400million. and we want to persist them in our postgres database
for ~5months.

The key transaction table is going to have ~450 Million transactions per
day and the data querying/filtering will always happen based on the
"transaction date" column. And mostly "JOIN" will be happening on the
"CUTSOMER_ID" column along with filters for some scenarios on customer_id
columns. Each one day worth of transaction consumes ~130GB of storage space
as we verified using the "pg_relation_size" function, for a sample data set.

As mentioned, there will be ~100K distinct "customer_id" but the data won't
be equally distributed , they will be skewed in nature for e.g. Some of the
big customers will hold majority of the transactions (say 20-30% of total
transactions) and other are distributed among others, but again not equally.

So my question was , in the above scenario should we go for a composite
partitioning strategy i.e range/hash (daily range partition by
transaction_date and hash subpartition by customer_id)?
OR
Should we go for simple daily range partitioning on the transaction_date
column?
OR
Range/list composite partitioning (range partition by transaction_date and
list subpartition by customer_id)?

Thanks and Regards
Sud