Someone’s marathon time improvement

This is what it takes to get to below 4 hours:

https://old.reddit.com/r/Marathon_Training/comments/1hnmb55/and_this_is_how_i_went_from_511_to_317/?share_id=rhfy0laKIOgwyx_ru_RTe

I did about 370 miles in 2024. Can I shoot for 450+? Might be too much actually.