Getting an A7iv but super confused. Any advice in appreciated!

Hi everyone! I’m about to update from my first camera (Canon 77D) to an a7iv & I’m SUPER excited. However I’m really scared to buy it & regret it later. This is the only camera I’ve ever used even tho I’ve been around a lot of other cameras. I had my older cousin choose the 77D for me because I was just out of school with almost no knowledge for cameras but I’ve loved photography/videography & editing since I was a kid.

Another concern is the rolling shutter & overheating. Is it that much of an issue?

Also, please let me know if I should go for it or not. I feel like it’s the perfect hybrid. Also, what lens I should go ahead with? The cheapest option is the 28-70 kit lens. However I really like the sigma 24-70 tho it’s a bit steep but it’s fine. I’m open to suggestions of other lenses too. I’ve been looking at all your pictures and I LOVE them.

Thank you so much. All advice is welcome. Keep creating :)