Hi
@Dimitris, and welcome to the site! Being a new user, I would always advise extreme caution, especially since your computer is important for your work. You don't want a mistake to happen... but they do sometimes when dealing with installing or modifying operating systems.
But we can at least sound out some possibilities for you to consider, and some with less risk of mistakes. One of the first things to determine is if your laptop has an older legacy BIOS (motherboard firmware) or if it has the newer UEFI firmware. I think Arch is capable of UEFI installation, but UEFI is more tricky. Also, I am not familiar with Arch at all, except with a few brief attempts where I realized that it is typically more difficult to install and setup than other distros. Would you possibly consider an Arch derivative instead, such as Manjaro, Anarchy, Antergos, Bluestar, or other? These derivatives are often much more user-friendly than the basic Arch Linux.
Also, rather than dual-booting, you would be safer to at least try to use Arch (or a derivative) in a virtual machine in Ubuntu if you have a fair amount of RAM. There are several applications, such as
VirtualBox, that will let you create a virtual machine, or more than one if you want to try more. Each virtual machine would need about 20 GB of hard drive space.
Another safe way is boot Arch (or a derivative) in "live mode" on either a DVD or USB flash drive. I'm not sure if Arch allows this, but some or all of the derivatives will. Running an operating system off of DVD or USB is slower than a virtual machine or than a full hard drive install, but the safety is that it will not make any changes to your system (or break anything)... and it will let you test whether the distro is compatible with your laptop hardware... to make sure that your sound and wireless network is working.
Spending some time testing with these safer methods can help you narrow down which distro you really want to install when you are ready to take the plunge and erase Ubuntu. Of course, at that point, you will also need to back up anything that you need to save before doing a fresh new installation. If you happened to create a separate
/home partition when you installed Ubuntu, this might be used in your new system too, but people often do not make this separate partition so a backup would be necessary in that case.
I have recently tried out Manjaro and Anarchy in virtual machines, and both are very fine Arch-based distros. I've recently read some good things about Bluestar Linux, and I'll be testing it out soon also. I have some spare computers that I can install Ubuntu and then also setup a dual-boot to try to help determine if I can foresee any problems that you might have, but this is still not perfect and while it may work for me, it may not spot troubles that you might still encounter.
So, some things for you to think about now. Let us know a little more and we will try to help get you going.
Cheers