To do step 8 of the flowchart in the new tax year or not?

With the new tax year coming up in the next few weeks, I am thinking about how to organise my finances next. On the flowchart, step 8 is the only one I have not done yet. With the new changed rules on the ISA's, this upcoming tax year will be the final one in which the way you can allocate your 20k is up to you.

I am wondering whether it's worth utilising the 20k completely on Cash ISA. I wanted to do 4k in LISA but Moneybox has stopped accepting transfers for this tax year. I have also never used stocks and shares ISA which I will admit I am hesitant - this is why I am leaning towards putting it in Cash ISA.

I am also not sure if it's worth putting it in LISA as there are new rules for this too.