Is the Samsung 970 Evo Plus a good choice for an Asus Rog strix b450-f gaming II motherboard? I'm not quite familiar with internal ssds speeds so I don't know what would be a good choice. I only want it to run a few games and Windows so I can deal with 250gb
Yes, Samsung makes one of the best SSD's out there.
970 EVO PLUS is a safe and good pick, you wont regret it, especially if you are moving from a HDD.
It will work with your motherboard.
If you are going with the 250GB version, be cautious of what you put on it, since 250GB is easy to fill.
Put windows on it and some lighter games, and you are all good.