Generally speaking, it is a VERY bad way to spend your money on a fully packaged system.
Instead, it is typically recommended to get a separate A/V receiver, that follows industry standards, then get speakers which you can connect to that receiver which are appropriate for your room and budget.
A/V receivers can have more, or fewer, HDMI inputs depending on the make/model and cost. So, a better Denon, Yamaha, or similar will have more HDMI inputs, and handle higher resolutions, etc. Cheaper A/V receivers will not have as much connectivity. But, as you get into cheaper A/V receivers you lose amplifier power, which can impact the sound quality as well.
So, you typically buy an A/V receiver with enough power for the room and speakers you are using. If you are planning to do 4K, having a receiver which supports 4K resolution should be part of what you are looking at. Most new receivers support 4K resolution as well as Atmos audio and high resolution audio formats over HDMI.
Then speakers are a vast canyon of choices. I'm not the best to give suggestions on what you SHOULD buy, but you will want to do some research here.
This isn't actually as complex as some make it out to be. You have lots of choices, and if you really care about good audio, then you can spend your time doing that research, but if you just want a solid jump, then I would give us a budget, your room size, and where speakers will be placed in the room compared to where people will be sitting for some recommendations.
I like to start at
www.accessories4less.com to get an idea of what is out there at different price points.