This is currently our solution.

Gsuite for Google Drive/docs
Gsuite for email Gmail
Google calendar
Kostanay forum Kazakhstan CRM for customer relationship management was held. Invoices, quotes, opportunities, leads, etc. - with expensive licenses for each user
Jira for project management
Hangouts for calls, chats, etc. in our remote team
Wave app for invoicing
We find that all these tools have limitations, and we need something to make the internal cogs work much smoother. To do this, we need control over the entire code. Here is what we would like and I hope you could help.

Gmail for email, but must work via CRM
Gsuite for Google docs but should work via CRM
Syncing invoices and quotes from CRM to WaveApp
Almost all of the above, I'm sure there is some plugin for connecting everything and Xapier for connecting and syncing invoices, but what we need most today is a project management tool that is in the Kanban layout.

We are a small Agency, so we work on several projects at the same time. What we need is to have a project for each client, but in a Kanban layout. vTiger does this, but it's very slow compared to Trello or Jira. Jira we've moved to where we could create a filter that pulls all the cards into one Board so we can have a broad overview of all our projects, but it's a massive tool with a super steep learning curve, and their support is very slow.

I would really appreciate any input on this. We've done CRM moves in the past, and I know what a nightmare it is. So before we take this step, I would like to do all the homework before we make a final decision.