This topic comes up monthly, and has for decades, and I keep giving the same advice. I feel certain my advice is better than anything here, because my advice is that the rules dont matter, the ONLY thing you can count on is inconsistency, you are at their mercy, and if you are counting on one set of rules you ARE going to get hosed eventually, so BE FLEXIBLE. I'm confident in this becasue I have personally proven it to be true. I dont care what anything says online, or what the law is, you CANNOT count on one consistent set of rules to be held to universally. I know exactly what the rules are, all I know with 100% certainty is that:
1) you can count on the rules to change without your knowledge,
2) you can count on the airline and the government to have different timelines for updating their info,
3) you can count on various people (who happen to have a controlling interest in your travel plans) having a different understanding of the rules,
4) you can count on different local policies (state, city, airport, tsa office, local airline boss, etc) on how they apply their (possibly unique) interpretation of the rules, which may or may not directly contradict any other set of rules.
5) If making your flight with gun accompanying you is your measure of success, you can count on losing any argument with a tsa agent or airline representative when push comes to shove.
Based on this I'd recommend allowing yourself time to jump through whatever hoops they have, I would prioritize padding because your case WILL get violently thrown a great distance onto concrete, absolutely count on needing a lock for EVERY place that is designed to accept a lock regardless of whether it is required, and I would bring a set of both regular keyed locks and a set of TSA locks, as I personally know people that were turned away for NOT having TSA locks. Put everything in the case, add an air pod, make sure your name and address and cell phone is prominently available inside and outside the case, smile, nod your head, say yes sir and yes maam, and enjoy being treated like a farm animal as you wait with a smile. If you count on the published rules, you WILL eventually have a problem. Be prepared for surprises and inconsistency and you will be fine.