Can you link the wallpaper ? :-)
For the limit : basically you need to ask yourself how many connection someone if able to do in a second to your server. As an example, my limit is always 15. A bit high but I’m sure I’m not blocking a legitimate one (either from myself or someone else)
For the ssh port : it’s true, but trust me you’ll be happy to change for something random like 5927 because you’ll have far less bit trying to connect or probe your ip, thus your logs won’t be cluttered!
You should take a look at https://www.youtube.com/channel/UCp3yVOm6A55nx65STpm3tXQ he does have a serie about doing something like this and go in depth in it