I did the 401 twice. Last time in December 2022. It is less technical than the 300 and more solution oriented. No more tcpdump scrolling up and down and left and right. Since you have 301, 303 and 304, you know about LTM, ASM and APM. Additionally from the Study Guide you can see that you should also know about BIG-IQ, AFM, SSLO.
The exam is rather old, so prepare also for older products or solutions like SWG and Websafe.
Take a look here: https://clouddocs.f5.com/training/community/f5cert/html/class17/class17.html
This link is EXTREMELY helpful to know what topics / question you will come across.
It will also hint you that Silverline and ICAP might be part of the exam. It's definetly helpful to know about these too.
Best of luck,