Exceeding spreadsheet limitations - need recommendation please

Hi all

I work in marketing and need to interact with very large files, currently csv on excel.

As our customer sets are growing, these files are now creeping up to 1million records each. I often need to do INDEX or V Lookups of one file againt another with... disatrous results. One file might have the purchasing data and another the payment data and I need to find patterns, solve problems etc.

I am not a technical user (hence Excel) and can't go directly against the database.

I've looked at things like Airtable, but the large number of rows and columns make this a non-starter for me.

All of the searching I've done has recommended Microsft Access, but as we work on Macs, this is not an option for me (since it's still a Windows only desktop app).

My idea solution would be something akin to Excel that runs on my Mac as a desktop application, where I can import all of the many spreadsheets I have and then interact with the data.

Since these are customer files, there are usually common indentifiers like username or email address.

I can't use anything cloud based, since I can't upload customer data.

TBH - I don't know if the thing I'm looking for exists, and the closest alternative I have found right now if FileMaker. I've used it in the past and remember it not being great, but if that's what there is, I guess I would live with it. I

Thanks in advance!