My Generatepress Website speed are very slow (4 sek.)

I have spent a lot of time making all my images smaller on all my pages because my website is very slow - we talk about 130+ images. But my website is still slow? Do you have any suggestions for making my website a least a little faster - then I will do something about it.
I would be very grateful if you could help me here!

Best Regards
Henrik
https://marathontrainingbuddy.com/