I tried Linux mint and other debian distros, and since i dont have the sufficient skill to manage linux, this time i’m choosing Kubuntu because of the KDE environment , which i like a lot

KDE is a great desktop and my personal favorite non tiling desktop. Very customizable! It can take a bit of time to set it up just the way you like. When moving to a new distro and using KDE getting your settings back the same as before can be a pain. Luckily there is konsave might come in handy in the future.

I know more about linux mint and kinda know how to work with him, but kubuntu never tried and i will try this time… but i have some questions if someone can help me.

Kubuntu is in the same family as Ubuntu. Mint is based on Ubuntu so you already know more than you think you do.

The ubuntu family of distros has great documentation and community to get help in as another commenter pointed out. Most of all your questions probably already have answers on their forums.

Kubuntu is ok for a new person on linux?

I think it is a good option for a newbie. Ubuntu is where I started my journey into linux many years ago.

I want to install apps/programms via flatpak, since this looks more easily for a newbie as me and because of the sandbox, which seems is good (?).

Flatpak is a great option for beginners! The sandbox is a nice feature. I dont really use them myself. Ubuntu has Snaps installed by default and snaps are similar to flatpak. Flatpak is a far better option IMO.

Make sure you read the Ubuntu or Kubuntu documentation on how to add the flatpak repo/PPA. If you get any errors you should search the kubuntu/ubuntu community forums for the right answers. If you cant find the answer you can always post there for an answer.

Other question is about flatpaks from flathub. I know flatpak usually dont follow the theme of my DE. Which is the best way these flatpaks have the same theme as my DE? Is using the flatseal? Any tip about this?

I have never used flatpak so I dont know the best way of theming them. Hopefully someone more knowledgeable will come along with a better answer than I have on this.

Other question I have, is about some apps i want to install if i dont find it or just find it on github or something similar. I find an app that really like but this app dont appear in any store, and this app is only available on github via flatpak and .deb . In this case, since the app is not available on flathub or diskover, or via command lines (like sudo apt install firefox - if you understand me) , how can i check this is not a virus or can do bad things on my linux? I use total virus for this, and the checks gives zero flags, but would like to know if for example, i install this programm via flatpak, can break my system.

Finding trusted software outside the official repositories can be difficult. Like the other commenter said try to vet the github app as best you can. You can always ask in the kubuntu/ubuntu forums. There might be a similar alternative app already in the Kubuntu apps.

Another option is to ask here on lemmy. People here might have experience with the app your interested in using. People here might know of a better alternative. Many of us lemmings are helpful geeks that are happy to help.

And, btw, if you can give me some tips and advice as linux/kubuntu newbie, it would be amazing for my journey. Cheers all!

Here on lemmy there is a linuxupskillchallenge@programming.dev community. It’s just a bot that posts about a free linux course. The course starts every month on or around the first. It’s a good way to get your feet wet so to speak.

Don’t worry if it’s a bit over your head. That’s how the best journeys begin. We all start somewhere.

If you have questions or problems the Kubuntu forums would be my first stop. You can always ask questions here on lemmy too. Like I said earlier, we are a bunch of knowledgeable nerds and most if us don’t mind helping or pointing you in the right direction.

Welcome to your linux journey.

I don’t Kubuntu but looking at their official page they have several community support options: https://kubuntu.org/community/

Haven’t used Kubuntu so can’t help you with that.

Regarding installing application from 3rd parties, there is no guaranteed way to know that what you’re installing is clean.

That being said, I would argue basic evaluations (how long has the project been around, does it get mentioned a lot in articles and forums, are there a lot of star and activity on the guthub page?) should be good enough for regular operational security.

One other general tip, try using Gemini (the LLM by Google) for real-time support and explanations around Kubuntu. I find it helpful for guidance on complex applications (ones that are far more niche than Kubuntu).