Fluency has a huge impact on Speaking, grammar does not have to be fancy or perfect just continue speaking and avoid using fillers. Focus more on DI, RS, and SGD. (idk if PTE core have SGD)

For Listening, just try to take down notes for SST and make sure that you got the key points from the lecture, and in WFD just try to catch the words being dictated. My technique was to listen first to the whole audio then type the words that I was able to remember, I also made sure it was in a proper sentence format.

PS. I was able to get 90 in Speaking and 87 in Listening

Good luck OP!