Performance Issues when loading excel files from folder and when doing steps in queries

Hey people,
I am facing performance issues in the power query and when refreshing the data.

My story is as follows:
1. I have placed 3 excel files in a folder a google drive and have used a folder query to get the files. (I cannot change them to CSV files)
2. I am constructed the data on power query to have on simple main table that has 6 columns and 3 rows, for the time being.
3. I have a main query where all the data cleansing is happening and I am referencing 6 times to get different queries where I am cleansing the data once more, specifically different for each query. At the end of these queries, I am referencing the simple main table to get the main information.
4. The data is not huge, all the rows in all queries might amount to 2000 rows for the time being.

Problem:
1. It is taking ages whenever I add a new step and whenever I refresh the data.

How can I make the it faster?

I have searched intensively on this topic. I cannot change the excel files to CSV. I have seen the option of using Table.Buffer but I do not know if it will work in my case and where to position in properly.

I would really appreciate any help on this.