How much character limit for domain name as seo point of view?
As far as search engines are concerned, it really doesn't matter at all. You want the domain name long enough to be meaningful and include your brand name or keyword/phrase, but not so long that people struggle to remember it and type it in.
There is no limit or optimal length for a domain in terms of SEO practices. You just need strong keywords or a solid domain referring to your site for SEO.