A lot of it is down to preference and budget.
If you search online you will find advice on buying monitors, more than can be given here. Have a look on YouTube.
There are a number of issues to consider. This article looks at some of them - https://gamingbuff.com/
You will also find advice on setting up monitors of different resolutions. It is possible, but there are some additional steps that you would need to take. It is unlikely to work with Nvidia Surround and bezel correction could be an issue.
Finally consider that a 1051ti will not run 3 monitors at 4K, so that will limit the max to 1080p.