massive lags

soo,i still got the same problem. i thought the 1.15.1 will fix my problem but they don't.
problem:massive fps drop i can only play at average 1-10 fps

when i use 1.14.4 there are no lags at all. mc running fine.
i think the problem is slow chunk rendering. any fix?
i already set the lowest setting as possible such as chunk distance and biome blend
help please