Integrate Elastic search with Firestore for a multi tenant SaaS platform (PoC)

We are currently building a SaaS platform which is like a CRM system but serves a different purpose. We are using Firestore as back-end and since it doesn't support free text search I want to do a Proof of Concept with Elastic search. We already have done a test with Algolia and I want to make a better trade off between those two products. Our application is multi tenant and will contain around 15000-30000 records per tenant. Some of the requirements are: - A global search that searches in all records a user has access to. - A search per modules(Accounts, Contacts, Products etc...) - A search for a specific field inside a module (Search for Account name), with queries like absolete==false - Records from firestore needs to be synced towards Elastic (Create, update, delete) I also expect someone who can explain the different options of Elastic (Elasticsearch Service, App Search Service, Site Search Service) and different hosting options. For this PoC we need to sync 2k records from firestore and build a basic search panel in Vue