restore controlfile from tag with no recovery catalog

this is on 11.2.0.4 with "No Recovery catalog" in place. I used the below command to create a special backup, so that it is not deleted by delete backup script(as our retention policy is set to 7 days).

BACKUP database FILESPERSET 1 FORMAT
'/path/to/backup/file/%d_TAG_NAME_%s_%U' tag 'TAG_NAME' keep until time
'sysdate+50';

Now I want to restore using this specific backup from this TAG. I know if i have recover catalog in place, i can connect to that, and do restore controlfile from tag='TAG_NAME' but how do i do the same when no recovery catalog.

Lets says i lost everything(datafiles, redo logs, control files, spfile)...from what i under about the "keep until" clause it should encapsulate everything(datafile, controlfile, spfile if its in place)... so now if i want to restore, as my control file is gone, how do i restore from these tags ?

I tried something like below but that does not seem to work...

run {
set controlfile autobackup format for device type disk to
'/path/to/backup/file/%d_TAG_NAME_%s_%p_%t_%U';
restore controlfile from autobackup validate; }

run {
set controlfile autobackup format for device type disk to
'/path/to/backup/file/%d_TAG_NAME_%s_%p_%t_%U';
restore controlfile from tag='TAG_NAME'; }

here are the RMAN config(show all) that i am using..

CONFIGURE RETENTION POLICY TO RECOVERY WINDOW OF 7 DAYS; CONFIGURE DEFAULT DEVICE TYPE TO DISK;
CONFIGURE CONTROLFILE AUTOBACKUP ON;
CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE DISK TO
'/path/to/backup/file/%d_ctl_%F';

CONFIGURE DEVICE TYPE DISK PARALLELISM 2 BACKUP TYPE TO BACKUPSET; CONFIGURE CHANNEL DEVICE TYPE DISK FORMAT
'/path/to/backup/file/%d_%s_%p_%t_%U';

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