Not necessarily, you have to think of technical webmaster work as overlapping with normal website development. However, it is not the same thing. Here is the work we do on a regular basis for a client which requires technical work:
- Configure XML Sitemap
- Configure Robots.txt
- Compress Images
- Implement Organization Schema Markup
- Implement FAQ Schema Markup
- Update for New Releases of Schema Markup
- Implement Lazy Loading
- Implement Cache
- Setup No Index Archives
- Setup 301 Redirects (Situational)
- Fix Redirect Chains (Situational)
Keep in mind that not every client requires this much technical work to be done on their site nor is it even possible based on what the site is built on.
Website developers are typically working on feature development for a site and building out interactive pages that might be chock full of integrations with other platforms. Everything we are working on relates to the scaffolding of a website and is primarily dealing with its HTML configuration. This means that we are primarily concerned with how a website communicates with Google, not necessarily the design or what abilities the site has for UX/UI.