My wider family have been using Telegram to keep in contact, but some of us are keen on moving to an alternative messaging app; we're a mix of Android and Apple users, with some options being off the table due to personal dislikes (this rules out at least Google apps, WhatsApp, and Messenger). The problem is I'm finding it difficult to find one that meets all the basic criteria (below), so hoped someone here may have some ideas.

* multi-platform (must have Android and iOS apps; ideally a web interface, browser extension and/or Windows app as well)

* allow the same account to be logged in across multiple devices [edit] including more than one mobile device (rules out Signal) and access all messages on all devices (rules out Viber)

* relatively straight forward to set up as many in my family aren't IT savvy

The last of these could potentially rule out Element, which on first use seemed to meet all our requirements - I'm struggling to easily create a family group in it, and I can see some family members being put off. Given its target audience, I'm not too surprised, but we want to ensure it's something that is easy to set up, doesn't require hosting one's own server etc.

Are there any products that people could recommend that may meet our needs?

Thanks in advance.