Applicability of Tax - Engineering consultancy services

I was an employee till July-22 and from Aug-22 have started Electrical Engineering Consultancy services firm with a sole proprietor. I am expecting my (as an individual) income to cross 20 Lakhs (April to July 4 Months salary and consultancy fees) for FY 22-23. As I understand GST is not mandatory if your turn-over is less than 20 Lakhs. Since, I do not anticipate turnover of my consultancy services to cross 20 Lakhs hence, I am not in hurry to register for GST. Have below queries if you can help 1. What will be the tax applicability whether GST / TDS when I have to submit Invoice? 2. What will be the % of tax applicable? 3. Since my consultancy firm is registered as sole proprietary firm I understand TDS @ 10% will be applicable and that will be counted as proprietors income and during ITR filling, tax applicability shall be as per income slabs on individual. Is my understanding correct? 4. As per agreement with my client, I can charge Tax as extra over my consultancy fees. But for a sole proprietory firm that do not have GST registration, Can I add/claim TDS over agreed consultancy fees in my invoice?