What should I do?

Hello Gabriel! Let's explore your options for upgrading your iMac 27" 2017 after the HDD failure. Each choice has its own advantages, so let's break them down:

1. **Replace HDD with a SATA SSD**:

- This is a straightforward option. You'll remove the broken HDD and replace it with a SATA SSD. It's a cost-effective solution that will significantly improve overall performance compared to the original HDD.

- You won't need to touch the M.2 slot or the existing 128GB M.2 drive.

- **Estimated cost**: Depends on the SSD capacity you choose.

2. **Replace HDD with a SATA SSD and Upgrade the M.2 Drive**:

- In addition to replacing the HDD with an SSD, you can also upgrade the M.2 drive from the existing 128GB to a spacious 2TB.

- This option provides both faster storage for your system (SSD) and ample storage capacity (2TB M.2).

- **Estimated cost**: Higher than option 1 due to the additional M.2 drive cost.

3. **Remove SATA HDD and Replace 128GB M.2 with a 2TB M.2**:

- This option removes the SATA HDD entirely, leaving only the M.2 drive for storage.

- You'll have a single 2TB M.2 drive, which is fast and spacious.

- **Estimated cost**: Similar to option 2, as you're still upgrading the M.2 drive.

**Considerations**:

- If you need more storage space, go for options 2 or 3.

- If budget is a concern, option 1 is the most economical.

- Remember to back up your data before any upgrades.

- If you're comfortable with the process, you can perform the upgrade yourself using guides like the ones provided by iFixit.

Ultimately, the choice depends on your storage needs, budget, and technical comfort level. Happy upgrading!