Don’t use SMS instead of iMessage though. Then all your texts will be sent across the network without any kind of decent encryption. And WhatsApp is almost unusable unless you consent to uploading all your contacts to Facebook. (IIRC this was the red line that got crossed that caused the WhatsApp founder to quit FB post-acquisition.)

Signal is a good recommendation, but you won’t be able to convince 100% of people you need to interact with over text to use Signal. You might convince friends and family, but not acquaintances or random people who might need to text with (like your electrician etc.)

Given the tradeoffs, iMessage is pretty good for day-to-day messaging.