I am student - I want to open a current account

I want to open a current account for my business. I haven't started my business yet, I am planning for it. I didn't file any ITR before. My first query is — (1) I don't have any gst number, even I don't apply for it, because my customer don't need gst bill from me. As of now I know if business turnover within rupees 40 lakhs per financial year, then I don't need gst number and also I don't need any input tax credit. Basically it's a retail sale business. I will purchase goods with 12% gst from wholesalers and I will sale those in my retail shop. My customer will not ask for gst bill. In that case do I really need gst number? My second question (2) — I have to open a current account. Because if I make transaction from my savings account when purchasing goods, I will surely get notice from IT department. Because savings account is not for high value transaction. But my question is how much can I deposit cash in my current account? Because I have to purchase goods. I am aware that I can't deposit cash more than rupees 50 lakhs in current account. If I deposit more than this, my bank will notify it to the IT department. Similarly I can't withdraw cash from current account more than 20 lakhs per financial year. If I withdraw more than 20 lakhs, my bank will deduct 2% tds, because I already told you that I didn't file any ITR before. I belong from poor family. I don't have any investment. The amount of money I earn, with that I can't even fulfill my daily basic expenses. So back to the topic, I don't have to withdraw cash from my current account. Because I don't need to withdraw cash for my business. I need to make neft rtgs transaction or upi online transaction to make payment when purchasing goods. In that case rupees 20 lakhs limit matter? Because I am not withdrawing cash, I will make online or neft, rtgs payments to the party when purchasing goods. If I pay rupees 25 lakhs per financial year to my party, do bank deduct 2% tds on (25-20)= 5 lakhs ? Remember that, I am not withdrawing cash, I am making online, neft, rtgs payments. One more thing I want to mention that deducting tds by banks for cash with comes under u/s 194N of income tax act. Although I don't have enough knowledge for taxation. Thank you.