I suggest you consider an external SSD instead of replacing the internal drive. I opted to get a 2TB Thunderbolt 3 SanDisk PRO G-40 for my base Mac mini M4. It's been working excellent for me. It tends to run a bit hot, so I have it up in the air in a cheap metal iPhone stand. That improves the air circulation around it, and being metal, I hope it acts as an external heat sink.
I have all of Logic's Sound Library on the external drive with room to spare. It's very, very fast at both writing and reading. Unfortunately, the price has almost doubled since I bought mine last year (tariffs?).
I still have my AppleCare+ warranty intact. Since wiping the disk and re-installing macOS 26, I make it a point to only install what I need on my base Mac mini M4. I install data libraries and support files on the external drive, not programs or plug-ins. My personal data gets written to iCloud, such as documents I created in Apple's (office) apps, Numbers, Pages, etc.
Songs, templates and custom keyboard shortcuts I create in Logic Pro are written to the internal drive, so I back them up to the external drive, and delete what I don't need anymore from the internal drive.
I DON'T use TImeMachine! It backs up anything you've ever had on your Mac, even files and apps you've deleted and no longer use. I realized I didn't need it with an Apple One subscription with 2TBs of iCloud storage.
Using iCloud, everything remains in sync between all of my Apple devices, Mac, iPhone, and iPad. Apple's integrated ecosystem works great for me! Yesterday I was working on a music chart in Apple Pages and I had it open on both my Mac and iPad at the same time. Some features are only available on the Mac, and other things are easier to do in Pages on the iPad. Using iCloud works really well for me and spares me needing all kinds of internal storage space.
