SOA vs Demat for MF

A complete newbie here. Please help me understand.

I am just starting my investment journey. I already have a Demat Account with Zerodha, which I intend to keep to buy stocks. I was planning to start Mutual Fund SIP using Zerodha Coin app, when I noticed the discussion around SOA vs Demat form of storing MF units. As I understand, many are in favour of SOA, but I want to understand which way is genuinely better?

My primary factors are charges (assuming I invest from Coin), security, ease of access (SIP / SWP / STP), tracking, and reporting.

Say, I'm buying 1 unit with ₹100 NAV, how much would I have to pay? And say, I sell that 1 unit after 3 years with ₹150 NAV, how much would I get back (pre-tax)? How much does the DP / Zerodha / SIP Transactions cost?