Hi @tim.young can I just add to this post that additionally, I’ve just been shown by @Aprada that if you want to update all existing records to include the recordid that can be easily achieved by using the task automatons and doing the following…
Create a text field to save the recordID (name = ID text i.e.), go to Automations > on demand task > update the record > set ID text to the record value of recordID. Be sure you switch the rapid update on to avoid executing table rules.
You can apply this solution also for connected record fields.
(Credit to @Aprada and full post here: Table Batch Option to Execute Table Rules)