Seeking Advice on SEO Challenges and Content Strategy for Website

Hi everyone, I’m a freelance website designer and am planning to start a digital marketing business with some friends. We're in the process of building a website for our business and aiming to create SEO-optimized content from the very beginning. Our goal is to establish a strong online presence, generate leads, and convert visitors into long-term clients by offering honest services, strong solutions, and a flexible budget. We want visitors from international location to submit their leads and requirements, allowing us to reach out for conversion, while also keeping them engaged with valuable information on the website. I’ve done some research on basic SEO practices and have started planning the SEO strategy. My action plan includes: 1. Deciding on the SEED KEYWORD. 2. Exploring alternative ways to describe the SEED KEYWORD. 3. Researching Keywords and categorizing them (informational, branded, navigational, etc.). 4. Planning the pages and sections of the website. 5. Preparing content with suitable keywords and adjusting it as needed. Before I start writing the content, I’d love to get some insights from those of you who have experience in this field. What kind of competition and challenges should I expecting and anticipating at the beginning stage of SEO? Also, how much should I expect to modify or update my content as my website grows? I found multiple tips over the internet but some of the tips and practices were contradicting to each other which got me confused on my action plan. Looking forward to your advice!