"Make yourself the best candidate you can."
I'll mention a couple of success stories that I'm aware of. Obviously there's hundreds, or thousands, that have similar resumes but havn't got called. Sometimes the addition to your resume might be the trigger that gets you the call. The fact is no one knows what triggers 'the call' but that shouldn't stop you from improving your resume as best you can.
And sometimes guys are trapped by the seniority system. That doesn't prevent you from standing out vs. your peers. Look around, almost everyone can identify friends or coworkers that you believe are going places and guys that aren't. Make yourself into the guy that is going places.
All the guys in the examples below had other duties, awards, education, etc. IE, no known holes except for the one's mentioned. Are they major holes? No. But they might have been in the biggest weaknesses in resumes that were fairly strong. They identified the weaknesses and fixed them. I don't know if the pilot hiring data bases can identify the drive to improve yourself but it can't hurt.
Military heavy jet guy. Transitioned to civilian cargo flying. Was pursuing a commuter job. I recommended continuing because it would add a couple of key areas that were missing from his resume - 121 ops and passenger ops. He got the commuter job, qualified 121, and got hired.
Retired military. Recommended getting 121 passenger job ASAP. He was going to wait. No, get moving. Would fill 'no 121' and 'no passenger ops' squares. Got qualified, got called. Awaiting 'congratulations' or TBNT.
Military guy with 121 FO experience. Different boat then the first two guys. "Get your military IP qual ASAP". He pushed for it and got it about 6 months earlier than expected. Got called, got hired.
All three identified potential weaknesses and corrected them. Sometimes the correction is possible, sometimes it isn't. I switched jobs three times, sometimes going 'backwards', to fix my resume when I was trying to get hired. The opportunity isn't always there as the industry has changed since then BUT that doesn't prevent an assessment of the current environment and identifying, and fixing, weaknesses if possible.
Working with another guy who's upgrade is still sometime in the future. Instead he's focusing on building up his non flying resume, both professionally and not professionally related. If his non flying work doesn't get him noticed I think he'll get called shortly after he upgrades.
Another guy was going to get another rating (not type rating) on his license. Trying to see if that triggered the software to reevaluate him. It doesn't hurt. Otherwise qualified.
And network. Pay attention. Job fairs. Yes, it's money. No known payoff. Except you'll never know if you don't show up. (I don't get a dime for pumping this)
Lots and lots of qualified guys. Don't stop making yourself better.
Good luck.