Hi,
many thanks for your message. You should consider to connect a HDD/SSD to your system an move your RootFS on it.
Do change SD card, you could have a look to this post. https://dietpi.com/forum/t/raspberrypi4-rpi4-upgrading-from-existing-sd-card-setup-to-boot-from-ssd/4555/1
Usually it describe how to move on a RPi4B from SD to SSD but it should work same way to move SD to SD. The Install section describe it very well how to create an image file and flash it on the new device.