How to force degraded mdadm raid1 array to start and mount on boot?

How do I force raid1 array(neither root, nor boot) without all components present from failing to start on system boot?

I am using Ubuntu 21.10. File system used is ext4.

Expected behavior

• Install a system with RAID1 and two hard-drives and boot the system with array in-sync
• Shutdown
• Disconnect one of the drives and thus boot, unexpectedly, degraded
• The boot should complete.
• Shutdown, and boot again, expecting degraded state.
• The boot should complete.
• Shutdown, reconnect disconnected drive, and boot again.
• The boot should complete, add the device to the array, the array should be resyncing, and results with system with array in-sync, just like at the beginning of the testcase.

Tried the following with no results:

1. set "BOOT_DEGRADED=true" in /etc/initramfs-tools/conf.d/mdadm (new file created) (not supported from mdadm-3.2.5-5ubuntu3 / Ubuntu 14.04 onwards)
2. set bootdegraded=true in grub
3. looked at #dpkg-reconfigure mdadm

Found this old article that uses an initramfs script, but it references currently non-existant config files. Is this the best/only way to achieve the desired behavior?

Including output of cat /proc/mdstat and mdadm --detail /dev/mdx before and after mdadm --run /dev/mdx

    ~$ cat /proc/mdstat
    Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] 
    md126 : inactive sda3[2](S)
          124861440 blocks super 1.2
           
    md127 : inactive mmcblk0[0](S) sda2[1](S)
          243890176 blocks super 1.2
           
    unused devices: <none>
    
    ~$ sudo mdadm -D /dev/md/store
    mdadm: cannot open /dev/md/store: No such file or directory
    
    ~$ sudo mdadm -D /dev/md126
    /dev/md126:
               Version : 1.2
            Raid Level : raid1
         Total Devices : 1
           Persistence : Superblock is persistent
    
                 State : inactive
       Working Devices : 1
    
                  Name : asus-x200la:store  (local to host asus-x200la)
                  UUID : 8536f840:806e8d2f:b576dbe4:38ea1de6
                Events : 3840
    
        Number   Major   Minor   RaidDevice
    
           -       8        3        -        /dev/sda3

~$ sudo mdadm --run /dev/md126
mdadm: started array /dev/md/store

~$ cat /proc/mdstat
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] 
md126 : active (auto-read-only) raid1 sda3[2]
      124860416 blocks super 1.2 [3/1] [__U]
      bitmap: 0/1 pages [0KB], 65536KB chunk

md127 : inactive mmcblk0[0](S) sda2[1](S)
      243890176 blocks super 1.2
       
unused devices: <none>

~$ sudo mdadm -D /dev/md126
/dev/md126:
           Version : 1.2
     Creation Time : Fri Oct 22 19:05:29 2021
        Raid Level : raid1
        Array Size : 124860416 (119.08 GiB 127.86 GB)
     Used Dev Size : 124860416 (119.08 GiB 127.86 GB)
      Raid Devices : 3
     Total Devices : 1
       Persistence : Superblock is persistent

     Intent Bitmap : Internal

       Update Time : Tue Oct 26 19:11:58 2021
             State : clean, degraded 
    Active Devices : 1
   Working Devices : 1
    Failed Devices : 0
     Spare Devices : 0

Consistency Policy : bitmap

              Name : asus-x200la:store  (local to host asus-x200la)
              UUID : 8536f840:806e8d2f:b576dbe4:38ea1de6
            Events : 3840

    Number   Major   Minor   RaidDevice State
       -       0        0        0      removed
       -       0        0        1      removed
       2       8        3        2      active sync   /dev/sda3