Something I keep noticing in resumes I review and it bugs me because the fix is so easy.
People put their literal internal job title on their resume. The thing that was on the offer letter or in HR's system. So you see things like "Member of Technical Staff" or "SDE III" or "Associate Consultant" or "Engineer Grade B" sitting at the top of someone's role.
These are real titles. The company actually calls them that internally. So candidates use them. Makes sense.
Problem is that nobody searching for candidates is using those words. The JD says "Senior Software Engineer." The recruiter's keyword search says "Senior Software Engineer." The ATS keyword match is looking for "Senior Software Engineer." Your resume says "Member of Technical Staff" and it just doesn't connect.
Some ATS are smart enough to handle synonyms now. A lot aren't. And recruiters doing manual searches definitely aren't typing "Member of Technical Staff" into LinkedIn Recruiter or wherever. They search what the job ad says.
I was in a calibration call once where we were going through resumes for a backend role. Someone flagged a candidate as "doesn't have backend experience" and moved them to no. Two minutes later someone else clicked through their bullets and was like wait this person was literally doing backend, their title was just some weird internal designation. Got pulled back into yes. Lucky catch though, that's not how it usually goes. Usually nobody clicks through. They just trust the title and move on.
What I'd suggest: just use the standard industry title for the work you were actually doing. If you were doing senior software engineering work, write "Senior Software Engineer." If you were a tech lead, write that. Bullets need to back it up obviously, but the title itself should be the version recruiters and ATS are actually searching for.
Keep your LinkedIn at your official title if you want. Recruiters see both, it's fine, it's super common. The resume is the document being keyword-parsed though, that's the one that needs to match what the search is looking for.
If you've been applying for weeks and getting nothing and you have one of these company specific titles on your resume, change it. Of all the things to fix on a resume, this is probably the lowest effort highest impact one I can think of.