The problem arises with the Cubic interpolation, but you should really set the default interpolation to NoHalo which is usually better anyway(*). This will let you use your current version without undue blurriness.
There are also distro-independent versions of Gimp (flatpack and AppImage) that will run the latest and greatest without having to change your base distro. These also reintroduce the support for Python scripts which was removed by many distros because Gimp 2.10 uses a deprecated version of Python.
(*) AFAIK Cubic has been left as a default because it is less CPU intensive, but on modern machines this is not useful.