Transfer your site from 1C bitrix to another engine

The company’s management would like to move the site to another engine and make a redesign. The site should be modern, but in a conservative style, without designer fanaticism and empty “sophistication”.
Please let me know how much your development costs. About. And what are the deadlines? The engine is your choice.
If you have SEO experience, please write about how much external search engine optimization can cost.
Thank you.