How to replace non-boot hard drive without reinstalling my operating system?

I have an HDD and an SSD on my laptop. My HDD has a very high value of reallocated sector count (~10k) and it’s likely i’m going to have to replace it soon. I had dual-booted Windows and Ubuntu and I do not want to reinstall them all over again.

My boot partitions are entirely located in the SSD. Only Ubuntu /home and Windows drives (all except C:/) are placed in the hdd. I am planning to do the following:

1. "unallocate" the hdd partitions from both Windows and Ubuntu (i.e., make them visible as "free space")
2. Create a makeshift /home in the ssd, so that ubuntu still boots (is that even necessary though?)
3. Get the hdd replaced
4. Reallocate all the free space to both Ubuntu and Windows as required

Will this approach work? Or is there a simpler approach?

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System information:

• Ubuntu 20.04 (Linux gt 5.4.0-42-generic #46-Ubuntu SMP Fri Jul 10 00:24:02 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux)
• Windows 10 (will install all pending updates when I boot into it)
• 1TB hdd mounted on /dev/sda TOSHIBA MQ04ABF100 (JU001C)
• 120GB ssd mounted on /dev/sdb WDC WDS120G2G0B-00EPW0 (UI450000)