What should I know about transit visas and PCR testing for my complex flight itinerary through Malaysia and Singapore?

OK so due to 4 flight cancellations this is my new flight intinerary..Its insane.....any help would be greatily appreciated

Here is my flight schedule

Jan 31 - Beijing 9:55 - Jan 31 Guanzhou 13:25 (I have chinese visa so no problem) ---2 hr 35 minute layover

Jan 31 - Guanzhou 16:00 - Kuala Lampur, Malaysia 20:10 ---3 hour 10 minute layover

Jan 31 - Kuala Lampur 23:10 to (Feb 1) Penang, Malaysia 00:20 ---10 hour 45 minute layover

Feb 1 - 11:05 Peneang Malaysia 11:05 to (Feb 1) Singapore 12:35 - --6 hour 35 layover

Feb 1 - Singapore 19:10 to (Feb 1) Phuket 20:05

Yes i know this flight situation is madnes...haha

My questions for anyone that can help..

1. is it even possible for me to do this considering i need tr-pcr test thats valid from 72 hours from beginning of testing and if yes when should i get tested?

2. Will i need visa's or transit visa's for malaysia and singapore? All flights are on one itenerary but with different airlines....and im travelling with just a carry on

I know this post is long and crazy but any help at all will be greatly appreciated