Is there a way to filter by copyright (tag)? (Digikam)

I’ve just been playing with digikam and it looks really promising, moving out from Bridge since I have a large gallery over 12k and bridge is just too slow to navigate, the gallery has IPTC metadata, while trying Digikam it seems to fill all my needs, but I have one question and sorry if this was somewhere already, I looked in the manual and FAQ for this, for some time I’ve been using the IPTC core - copyright Notice field, and I just can’t find a way to filter via that field in digikam nor a way to modify the field if necessary, is this possible?

Also taking the opportunity, my gallery took over 5 hours to index, but after the SQL database was created, navigating is way faster which makes me happy, but, if I refresh the Album, will it do the index (and thumbnail generation) from scratch? or is there a way to just refresh to just update with the new images added to the folder?

Would really appreciate your help and insight, I’m thinking on updating the gallery, and this would be really important on whether or not I should keep using this field
Thanks for the help