Greetings.
Ubuntu 20.04 is using 100% cpu usage when I execute cpu intensive task, like web browsing or playing a game I have no idea whats going on.
Here are my specs:
Ubuntu 20.04 LTS
128GB Toshiba SSD
8GB of RAM
Intel Core i5-7200u Kaby Lake
2 Cores 4 treads
Max Clockspeed 3.1 GHz
Normal clockspeed 2.50 GHz
Graphics
Intel hd Graphics 620
Hi Diego. Have you looked a HTOPS app to see what processes you have running? Also, what if any programs do you have at autostart? Finally, have you asked the same question to someone in the Ubuntu community? (This is is the Ubuntu-Mate forum which is slightly different.). Thanks. 
Autostart apps:
Heres what htop looks like with google chrome and microsoft teams running:
Also what do the red numbers mean?
I may not have a full answer but MS Teams is using more virtual memory than you have in RAM. Your system has 8gb of physical RAM yet you are using over 13 and 40 gigabytes of virtual RAM. So the Teams app is doing something that is using up more resources than you have and you have no swap on either. I am not sure if the system is going back to your HDD or SSD. If you have have a HDD in use somehow, it would be a very slow. Also, if you have an SSD it would be taxing the drive’s life. I can only recommend to delete Teams and reinstall it, or not use the app and maybe use a web version if possible. Maybe someone in the forum has a better answer. Good luck!
Huh, that actualy makes sense now, I read from a reddit post that surface laptops ssd's can be quite slow
SSDs have a limited write life. So if the system or app is repeatedly writing to the SSD to compensate for a shortage in RAM, over time in theory the SSD will get slower. Of course there are some other variables that can contribute to that. I think the Teams app needs to be adjusted in the settings maybe or reinstalled. 
[UPDATE]
The Ubuntu Instalation is actualy 2 weeks old, I Had this computer running with windows for about 4 monts. I tried to run Benchmarks on the ssd the read was about 660, the benchmark however, could not be completed as it crashed the 2 times that I tried to run it.
Here's what htop looks like when I run Minecraft:
