Looking for a CRM to increase customer retention for a small SaaS business

I run a small SaaS business in the UK which is a product that I've built myself and I am now looking to improve growth and retention of my customer base by reaching out to trialling customers and following up.

Currently I use ActiveCampaign for newsletters, but I am in the process of moving to Customer .io as I find their event driven system to be much more powerful (e.g enroll the customer in a sequence of emails when they view a certain page or use certain features).

Now though I'm looking for a system to help with the following funnel:

• user signs up for a trial, after 1 day I get a "task" to reach out to them via phone call
• if they answer the phone, create a task to follow up with them via phone call before their trial ends
• if they don't answer the phone, automatically send an email inviting them to book a call on my calendar link
• remind them a few times throughout the trial to book a meeting if they haven't yet booked one
• also follow up phone call after 3 months to see how they are getting on, again with the same sort of automated emails if they don't answer

I really like customer . io for more generic emails, but it can't really be used as a CRM as there's not even a way to add notes to a contact (that I've found). So I'm looking for tools that can help with this level of automation. I'm using it primarily to engage with existing leads to build relationships and increase retention, not cold emailing prospects.

So far I like GoHighLevel's automation the most, as it's quite powerful, has webhooks etc as well to automate things in other systems, however GHL seems extremely slow and buggy, and I cannot stand the user interface, so ideally I'm looking for alternatives.

It would be good if the follow up emails appeared as part of the same email thread as well in the user's inbox, something which GHL can't do at the moment. Also some kind of dialler or calling capabilities to help go through the call tasks and log notes and the outcome to progress the automation would be amazing.

I've tried the following tools as well and found their automation capabilities to be fairly limiting, for example no webhooks or integration with other services, so I'd really appreciate any alternatives in the space that you might recommend!

• reply .io
• apollo .io
• outplayhq.com
• Hubspot, have been using this anyway but am now trialing sequences, they seem extremely limiting

Thanks!