It's just disabled by default, unavailable in group chats or channels, and enabling it reduces usability (i.e. you can't use multiple devices to chat if you enable E2EE).
Telegram as a chat app has the best UX of any chat app out there in my opinion, so the lack of proper E2EE is simply disappointing. I don't really trust either, but I consider WhatsApp more secure than Telegram, despite Meta mining my metadata.