Minecraft little FPS, although I have good PC?

I have a new PC for a few days

Processor: AMD Ryzen 2600 6x 3.9 GHz

Graphics card: AMD Readon RX Vega56 8 GB

And unfortunately, I have to say that I only have strong FPS drops in Minecraft.

According to Agando, where I bought the PC, I should have 600 FPS at maximum settings.

However, I only have between 50 and 110.

When I'm in PvP, they usually drop further

Have Minecraft already assigned 8GB of RAM, which has only slightly improved.

What else can I do?

The 600 FPS are of course nonsense. Maybe with minimal settings, if you look at the sky.
Minecraft is not the game to measure the performance of a computer now.
Depending on which mods / shaders you use and how much is going on in your chunk, it can be normal that it's only 50 fps.
If you only bought the PC for Minecraft, that was quite overkill.

Is normal at minecraft. As long as it's 60-70fps, that's okay.

You can believe the fps information or not but not at vendors.

What would you like with 600fps?

I was just wondering why I have so little when the page says it should actually be 600.

That's the thing, I do not use TPs, mods only Optifine and fps I've tested in single player.