Please read this link and post the output here.
The results will provide a lot of info we will need to assist.
You also might try several different commands in a terminal and provide the outputs so we might see additional specific details.
dnf list --installed kernel\*
df -h
ls /boot
Please post the output from each command as preformatted text, which is done by copying the text from your terminal and pasting it here, then highlight that text and click the </> button on the text entry window toolbar.