Yep latter is what I'd suggest i.e. use a longer lens, crop less and get the field of view you want optically.
But what I mean is, say you stitch 5 shots from A7RIV you end up with a ~250mp file. What are you going to do with so many pixels?
With a 24mp body you end up with more like 80mp image which is plenty even to be printing massive sizes unless you are wanting to print billboard sizes and look at them with a magnifying glass.... but then I think you have other bigger problems than lack of megapixels