CRM Recommendations Needed for Pre-Filing Benefits Consulting Firm

Hello! I'm looking for recommendations for a CRM for my consulting firm. There are currently 4 of us, and we basically streamline and automate the completion of benefits applications for eligible individuals. We've had about 200 customers so far, and send out 10-20 contracts a month to be signed.

We've been using Google Sheets tabs as our list of clients with dropdown values to identify which stage each client is in in the process, but this is difficult to keep updated because a lot of things depend on external factors, and we get updates from clients as they get them, which is at any and all times. There's also a lot of information we need to track about each client, with the information being different and unique to each client.

I don't know that we need a CRM for a large business, what we'd prefer is one that is for a small but growing business and integrates with a lot of the services we use right now, in order to automate a lot of the manual tasks we have to do currently. We currently use Google Drive for file storage for our client's paperwork, Google Sheets as our "CRM" (really just columns with customer information in it), Square for contracts, invoices, and its Customer Directory, Trello to assign tasks to ourselves and team and to track what's getting done. I'm the only one currently that communicates with customers, so we're looking at hiring a 5th person to take over all the customer communication and customer information management, and to keep the CRM updated, and do all the manual tasks that need to be done, until we can automate everything we can.

Any recommendations are appreciated, thank you!