slow SQLite read speed (100 records a second)

I have a large SQLite database (~134 GB) that has multiple tables each with 14 columns, about 330 million records, and 4 indexes. The only operation used on the database is "Select *" as I need all the columns(No inserts or updates). When I query the database, the response time is slow when the result set is big (takes 160 seconds for getting ~18,000 records).

I have improved the use of indexes multiple times and this is the fastest response time I got.

I am running the database as a back-end database for a web application on a server with 32 GB of RAM.

is there a way to use RAM (or anything else) to speed up the query process?