Wondering if someone can help with outlining the key benefits, restrictions and differences between Microsoft Access, Power Pivots in Excel and Get and Transfer data function?

I have two separate documents of data: one product sales by line by store and one with stock holding by line by store. Both files are very large (>30,000 lines of data) with excel struggling to manage and both files are not formatted in a way that is possible to do simple v-lookups to merge data. Ideally would like to merge data then have flexibility to analyse from different angles - as you can within a pivot table.
Worth noting I have this data for multiple countries and would also like to review together/totally but for now fine to focus on by country first.

From reading reviews online feel that Power Pivots, Get & Transfer data and Mircosoft Access could offer something along these lines but would like some further information before investing time in one.

Thank you for any guidance and support you can offer with this.