Correctly using the Capital Gains Account Scheme Proceeds

Hello,
I have some amount sitting in CGAS account and wanted to confirm how that amount can be effectively used.

Let’s say for example - I have 50 Lac in CGAS schema and I purchase a house for 35 Lac. What happens to the remaining 15 Lac amount?
Can I transfer some amount(let’s say 10 Lac) out of 15 Lac into my savings account in the name of Registration/Stamp Duty, Brokerage, Lawyer, Renovation costs, etc. and then withdraw it from my savings account to use it for these services?

And then transfer if any remaining pending amount in CGAS (in this case 5 Lac) to my savings account and pay 20% tax on this amount.

And the interest amount which is already tax paid during ITR filing, can that also be transferred to savings account?

So, just want to confirm if the CGAS amount is used strictly for the house purchase or it can be used for other additional services occurring during house purchase. And if any proofs needs to be shown to the bank to transfer the amount to savings account to use for these services.

Thanks.