inspiron 3030

My Inspiron includes a 1 TB M.2 SSD drive and an NVidia 4070 GPU.

I bought it with the intention of adding a significant amount of internal storage.

According to the documentation, I should theoretically be able to add a second M.2 SSD and up to 2 SATA 2.5" or 3.5" HDDs.

I didn't want to buy the Dell SSD or HDD because they don't have sufficient storage.

(The intended user is an image/video packrat who doesn't understand how to use external drives.)

What I am looking at are:

Crucial P3 Plus 4TB PCIe Gen4 SSD (M.2)

Seagate Exos X20 ST20000NM007D 20TB 7200 RPM 256MB Cache 3.5" Internal Hard Drive

Dell Tech Support wasn't helpful, wanted to refer me to sales even though I explained why I didn't want to buy Dell drives-insufficient storage for intended usage.

The manual wasn't terribly informative, MB and chassis diagrams not nearly as those for separately purchased MBs and chassis.

Has anyone else tried to expand storage in the model using non-Dell drives?