SOLVED!
KB5034441 successfully installed.
I used some steps here: KB5028997: Instructions to manually resize your partition to install the WinRE update
Summary of my steps:
Steps 1 to 3:
reagentc /info
Note: partition 4
reagentc /disable
Run gparted, adjust partitions.
Reboot.
Note - I had to increase the size to 1000MB for this to work, not 750MB.
Open CMD as Administrator:
diskpart
list disk
select disk 0
list part
sel part 4
DISKPART> list part
Partition ### Type Size Offset
Partition 1 System 100 MB 1024 KB
Partition 2 Reserved 16 MB 101 MB
Partition 3 Primary 464 GB 117 MB
Partition 4 Recovery 1007 MB 464 GB
Note: skip the 'shrink' command.
delete partition override [must delete partition]
Continue entering the commands in diskpart:
create partition primary id=de94bba4-06d1-4d40-a16a-bfd50179d6ac
gpt attributes =0x8000000000000001
format quick fs=ntfs label=”Windows RE tools”
list vol
exit [diskpart]
reagentc /enable
reagentc /info
Restart Windows 10
Install KB5034441.