What can I expect when upgrading from an entry level camera?

About 5 years ago, I was going on vacation and bought my first DSLR, a Canon 1200D on sale for about $100. Between then on now, I've used it for mostly travel photography, portraits, a couple products shots over the years as well as some personal projects. Over the past 2 years specifically, I've noticed some short comings.Firstly low light is virtually unusable. Even photos taken near the end of golden hour often look a bit muddy.Dynamic range is not great. Almost any photo taken during the day either has bright white blown out areas or pitch black harsh shadows.Noise levels are very high for any photo not taken in perfect lighting, which from my experience is during the day in the shade. Even photos taken on rather bright cloudy days can be full of dots.So since my financial situation has changed dramatically since then, I want to start experimenting with video, and I want to start doing a lot more paid shoots, I've decided to get myself a Sony mirrorless (at the moment deciding between an a7III and a7s3).My question is what are the realities I should expect with this upgrade? I've watched countless reviews but just want to know the experience of other people who have gone through a similar upgrade via /r/photography https://ift.tt/3hrR2as