Push Notification - filed "To" limitations

As I understand Push has limitations of 100 messages batch at one request,
however, each message has the field To which take a list of PushTokens, are there limitations to the number of recipients in that field?

Example of the worst-case scenario: organisation send an email to the distributed list All so basically all employees of the organisation will get an email. We need to send push message to notify users that new email has arrived
In that case, we have just one - single push message with a single body, however field To will include a list potentially of 1k+ tokens = all employees

Any limitations here? should it also be batched somehow?
I didn’t find any info in official documentation regarding limitations of field To

Also question regarding response in the case described in previous post

Assuming we send 1 notification with multiple receivers defined as list in field To, as I see in the example in official docs:

According to docs I will get only 1 ticket per 1 msg end, but in case of list of receivers some of them could succeseed, some not if some tokens will be invalid, will the response be still with status ok?
will there be error per each invalid token so we can remove them from our system?