Move an existing Ubuntu installation to new disk that i've configured it with lvm - a few specific questions

I've been searching the internet for any answer to this and have not found anything that I can wrap my head around, not that specifically answers my questions anyway.

I installed a new hard disk in my computer and I want to move my existing 20.04 Ubuntu installation to it using after setting up lvm physical disk/volume group/logical on the new disk (prior installation didn't have lvm and I want to convert it to lvm and move everything back so I'm going to be doing this again after I re-partition the old disk)

I ran all the commands to get my lvm setup like I want it (except I want to pull out the /home and put it on it's on logical volume which I will do on the return trip)

These are a couple of articles I've read and though they are helpful I am getting some issues getting my system to boot off the new disk and I must be missing a setup step that allows lvm to boot:

https://ilearnedhowto.wordpress.com/2020/04/23/how-to-move-an-existing-installation-of-ubuntu-to-another-disk/

https://www.thegeekdiary.com/centos-rhel-converting-an-existing-root-filesystem-to-lvm-partition/

I'm aware the second is for a different flavor of linux...

First here is fdisk for /dev/sdb:

root@Uranus:~# fdisk /dev/sdb

Welcome to fdisk (util-linux 2.34).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.


Command (m for help): p
Disk /dev/sdb: 465.78 GiB, 500107862016 bytes, 976773168 sectors
Disk model: WDC WD5000BEVT-2
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0xf43e5cfa

Device     Boot    Start       End   Sectors   Size Id Type
/dev/sdb1  *        2048   2099200   2097153     1G 8e Linux LVM
/dev/sdb2       20992001 976773167 955781167 455.8G 8e Linux LVM

and lvs

root@Uranus:~# lvs
  LV   VG     Attr       LSize   Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
  lv1  boot   -wi-a----- 512.00m                                                    
  lv2  ubuntu -wi-ao---- 419.00g                                                    
  lv3  ubuntu -wi-ao----  36.00g             

                                   

I got all the stuff move to the new lv2 volume using:

root@Uranus:~# tar -cvpzf /mnt/lv2/backup.tar.gz --exclude=/mnt/lv2/backup.tar.gz --one-file-system --acls --xattrs --selinux /
root@Uranus:~# tar -C /mnt/lv2 -xf /mnt/lv2/backup.tar.gz

I also did the above commands for /boot and placed that on the boot logical volume

I updated my /dev/lv2/etc/fstab to mount / and /boot from their logical partitions using the UUID's.

At this point since I'm dealing lvm I am trying to figure out what command to get the new disk to boot after I go into bios and change the boot order.

I ran dpkg-reconfigure grub-pc but that wiped out the /boot on the new logical partition.

here is the fstab:

root@Uranus:/mnt/lv2/etc# cat fstab
# /etc/fstab: static file system information.
#
# Use 'blkid' to print the universally unique identifier for a
# device; this may be used with UUID= as a more robust way to name devices
# that works even if disks are added and removed. See fstab(5).
#
# <file system> <mount point>   <type>  <options>       <dump>  <pass>
# / on /dev/sdb2 during installation
UUID=b0f9cf0b-55ed-4d9e-bda9-d55f47b64d46 /               ext4    errors=remount-ro 0       1
# /boot/efi on /dev/sdb1 
UUID=3e51c0bc-46e3-4394-8b0b-ca7aaee4eb54  /boot/efi       ext4    umask=0077      0       1
# boot swap space on logical volumn /dev/ubuntu/lv3
UUID=626fdd18-ce48-4498-bba7-baa9ccebde93  none            swap    sw              0       0

How do I get grub to boot the logical volumes and properly load / ? Keep in mind I haven't gotten that disk to boot yet so I need to have whatever program run to make it "bootable" other than the flag from fdisk.

Thanks in advance.