I did some digging, and it looks like your mobo was used mostly in the k450e desktop computers like this.
If that’s the case, your upgrade options are going to minimal. Space isn’t a huge issue, but one thing I also forgot to mention in my last comment was the power supply. I just about bet the psu in that one wouldn’t be able to support much more than what is already in there. Any newer graphics card worth using on the sim will require at least one (often two) PCIe power cables direct from the psu, and I wouldn’t be the least surprised if that one doesn’t have any at all. That means it would need upgraded, assuming the current one is used serviceable and not riveted in or some other goofy setup.
The cpu power connection looks to be a 4 pin on the board, so I would expect that as well on the psu. Modern cpu’s would likely need more, so a 6 or 8 pin connection unless it’s a very low power CPU.
Also, the ventilation on that case looks bad, which could severely impact performance if upgrading in it. Remember, these systems are built to their respective specs and nothing more, meaning little flexibility with aftermarket upgrades.
I think you have a few options depending on your budget. The cheapest and easiest would be buying a used complete system. Something in the $400-500 range should do ok, and you may find something for less.
The next cheapest would be to buy your own parts and build it yourself, which could be a mix of new and used parts, depending on budget and how much you desire warranties and trust used items. This also requires you to be ok with putting everything together.
The easiest, but most expensive route would be to buy a new complete system. This theoretically gives you an out of the box ready to run system with a full warranty, but now you may be limited on the quality of parts and assembly, or companies like Dell/Alienware that try to sell you an extended warranty that happens to come with a computer full of proprietary parts that you can’t easily replace or upgrade.
We can help you figure out what to go with if you can give us a budget, your monitor resolution, and what you want in terms of performance. I know you want clear ground textures, but that can be subjective in what you consider acceptable and doesn’t account for things like if you run AI traffic or use add-ons.