minecraft version 1.19 is too strenuous for my computer but the frame rate ingame shows something else

What I expected to happen was...:
the frame rate would probably be 40 fps lower and thats all

What actually happened was...:
its 200 fps lower + the frame rate ingame isnt right

Steps to Reproduce:
1. take an budget gaming pc

2. open minecraft (1.19)

3. make an world

4. click f3 and see the frame rate

5. check if it really is that frame rate like it shows there