I have all my savings in an ISA - but now I want to transfer it into a LISA to buy my first property? Advice / insight please

Hey all. I am 30 years old and at around 25 started saving very little every month into an ISA. I have now got £12k in that pot. However, I never did any LISA contributions because i didn't think I would ever own a property before 45. My circumstances have changed and I am now potentially looking to buy in next 5 years (family have let me know they are planning on financially supporting me on my deposit, and my income has increased significantly).

A) Is transferring 4k per year into a LISA from my ISA a bad idea? I am with moneybox so i dont believe they have a fee for withdrawal.

B) Or, as my income has really picked up I can just start dumping 4k a year from my income starting today? And let my ISA just do its thing? Not sure if contributing more than 4k/year is really necessary to reap as much out of it as possible?

Apologies for my naivety, I genuinely never really considered my financial future beyond just putting a little bit away every now and then.