It probably will. A big old squirt of ‘framesaver’ should fill them same corners. This has been my go to for a few years now. One can will do about a dozen frames.
Water will still get in past the seatpost. Through winter I get in the habit of of removing my seatpost and tipping the bike upside down every month or so just to check it’s not accumulating. I know some people who used to remove their seatpost after every wet ride to let things air out but with a dropper post that’s a bit of a pain.
Also, I know of at least two builders who often don’t put any vent holes on their bikes, and I have a couple bikes built like this. One is this exact frameset built with relatively light tubing (.8/.5/.8) and has over 35,000 km without issue.
Most tubes are sealed, the ones which are open get treated with framesaver.
Would their be a specific TIG sequence that allows you to seal up the tubes with the final pass. Anyone else aware of such a process?