So you now purged the kernel packages that only had config files left (rc state).
Your EFI partition still has too many kernels installed though, preventing apt do make adjustments.
To solve that, you manually need to clear out the EFI partition. See for example:
Ok, too bad. In case you only want to keep the 7.0 kernels you can mount your efi partition and manually remove all the 6.x initrd.img and vmlinuz files there to make space so the apt process can complete.
mount /dev/disk/by-uuid/665C-E3E3 /mnt/efi
rm /mnt/efi/initrd.img-6*
rm /mnt/efi/vmlinuz-6*
Then do a check to see if the efi partition now actually has space with df -h /mnt/efi
And more elaborate: du -ah /mnt/efi to show all files on the efi partition and their sizes.
Then umount /mnt/efi and apt purge proxmox-kernel-6.* again.
If all...
No, you apparently have 2 EFI partitions configured, probably a mirrored disk setup.
Mount both EFI partitions:
mkdir /mnt/efi1 /mnt/efi2
mount /dev/disk/by-uuid/A437-70EE /mnt/efi1
mount /dev/disk/by-uuid/A438-D2C2 /mnt/efi2
Remove the old 6.* kernels:
rm -rf /mnt/efi1/EFI/proxmox/6.*
rm -rf /mnt/efi2/EFI/proxmox/6.*
Umount the EFI partitions:
umount /mnt/efi1 /mnt/efi2
rm -rf /mnt/ef1 /mnt/efi2
Purge the 6.* packages:
apt purge proxmox-kernel-6.*
Try the update again:
apt dist-upgrade
dpkg -l | grep...
