Your usage sounds light enough that you won’t notice any performance difference.

The processor isn’t the only thing to consider, though. The M2 has a brighter screen, better webcam, and MagSafe charging which can free up an extra port for accessories. I personally feel that those features are worth the price difference.

You need a hub/dock that supports Thunderbolt.

Here’s one from OWC if you want to stick with them: https://www.owc.com/solutions/thunderbolt-hub

I still have 2 Months warranty but if IceTea or whatever got spilled on the keyboard apple wont fix it for me unless i pay for it ( so no warranty will apply i guess).

Bring it to Apple and have them take a look?

If the key is sticky because of a spill, then you’re right that it won’t be covered under warranty. But you don’t know if that’s what happened.

macOS comes with built-in antivirus protection:

https://eclecticlight.co/2022/11/01/everything-you-need-to-know-about-xprotects-malware-protection/

Yes, but note that you’ll probably need to install extra software to get the scroll/buttons working the way you want. Logitech’s software is garbage, but there are third-party options like Steermouse.

That other port is for Thunderbolt 2:

https://support.apple.com/kb/sp714?locale=en_US

Search for “Thunderbolt 2 to HDMI adapter” for options. Here’s one:

https://www.amazon.com/Plugable-DisplayPort-Supports-displays-3840x2160/dp/B00S0BWR2K

There is no way to tell without having the MacBook in your possession and poking around.

Can you post screenshots of the CPU and Memory tabs in Activity Monitor? And also let us know how much free space you have left on your disk?

I don’t think there’s any need to upgrade now if it’s serving you well. At the very least, you should be good for security updates for another two years.

There are still plenty of advantages to upgrading, of course. Even if you don’t need the extra processing power, the longer battery life could be quite useful.

(And we’re not talking small differences here … modern MacBook Airs offer like 5x the processing power and 3x the battery life.)

When I'm reading a bit on apple's website, everyone says it's normal, but I don't understand how 2 people could have this much different results

There are many factors that contribute to battery degradation. Cycles and age are factors (as you’ve already identified) but also heat and differences in manufacturing.

So, maybe you run more intensive apps than your girlfriend and, because of that, your battery gets warmer. Or maybe she just got a good battery from the factory.

This is why all of the situations that you’ve described are considered normal.

Which dock?

You need a Thunderbolt adapter/hub/dock to get two external monitors working. Non-Thunderbolt USB-C docks rely on MST (multi-stream transport) which is not supported by macOS.

There are many Mac apps which are not available through the App Store. You should get them directly from the developer’s website.