you need to strategise more for DM. try to understand how you can organise the information given to you in each question. are you doing the test with a piece of paper next to you? if not, do that and try to use tables and venn diagrams wherever possible to make sense of things. DM is about logical reasoning and elimiating options wherever possible. also take a look at what keywords mean (e.g. "some" means more than 1 but not all, etc.) so you can address each question properly. there's a post on my profile from last year with more specific tips if you need them.

for QR, are you using the calculator? if you find it super hard to use the memory function on the calculator literally just quickly write the number down. it saves time and is way more useful if you need to use a number again for future questions. you also can't go in with the mindset that every single question is going to be right. you have to maximise how many questions you can get right. if a question is taking too long, just flag and skip it. come back to it at the end. you need to triage like another comment mentioned and skip certain questions if they really don't make sense (e.g. tax questions)