Can Zoho handle 30k + contacts?

Yes, there is no limit on the number of contacts you can have.

If you select to use the Professional license, see attached, then you can import up to 10,000 contacts at once, so we would need to import three batches, it takes just a few minutes per batch. The format is excel or csv, we would need to look at the data structure and customise the CRM to match you needs before import. This would not take long and we have extensive experience in doing this.