There are rules for how to craft magical items in the DMG and other books. It is the default option in the game.
RAW very few campaigns are going to afford fighters the opportunity to craft anything beyond uncommon items. You might be able to squeeze in 1 rare item over 10-15 levels, working for a while, then adventuring, but even that is situational.
RAW to make this work you a need:
1. proficiency either in Arcana or a tool set you use to craft (situational).
2. You have to find the ingredients (not that hard but has to be built into the plot and the rest of the party need to agree)
3. get the cash (not hard in most campaigns)
4. Find the downtime (almost never available for anything beyond uncommon items and again requires party agreement).
Also consider, this thread is centered on the idea that Fighers are limited, especially in non-combat pillars. RAW if you have downtime to craft very rare magic items for high level play then you also have downtime for skill training.
Some DMs remove these options, but I've played with a lot of DMS - and it is rare, and usually setting specific, when it does.These feats add to your tool belt. They do not restrict it. They also do not stand alone. They combine with your subclass abilities, and present other options. When I use a polearm, I am very cognizant that I am holding a long metal rod that can manipulate the environment up to 10 feet away. While people till continue to tend towards attacking with good attacks, you also need to consider the control elements this combo brings.
You can bring more control with other feats. Magic Initiate, Fey Touched, Crusher, Slasher and Shadow Touched come immediately to mind.
It has been lauded, since the start of 5E, as one of the only real 'defender' control tricks out there (especially when combined with sentinel).
By people on message boards and in a whiteroom. And I am not saying it is aweful, but it is not great either. With Sentinel you are now talking 3 feats GWM/PAM/Sentinel on this hyper-optimized, narrowly focused build and you are gobbling up your bonus actions and reactions while not taking a single ability increase until level 12 (or level 8 if you got a 1st level feat.
You're assuming this has to limit options when that remains entirely in player hands.Superior Technique is not an alternative to a feat - it uses a different resource.
Martail Adept is an alternative to PAM. It is not a great feat. When combined with Superior Technique as a fighting style it is going to bring more control than PAM+GWF will.
Martial Adept + Superior Technique means you can use a maneuver in every fight if you follow the two fights a short rest pacing. More than that if you do more short rests like most campaigns.
Regardless, having two superiority dice from these approaches can be fun for 2 attacks per short rest.
Which is generally once every fight with standard pacing. If your aveeerage fight is 4 rounds you are talking about being able to use a maneuver on 25% of your turns.
I think that is more often than you are going to be able to use the PAM-Sentinel AOO, will provide more powerful effects when you use it, and it costs one feat less.
. I'm not saying it isn't a good idea ... just one that diminishes in utility over the phases of the class. I've seen Battlemaster be popular at lower levels, but it is common for higher level players to struggle with 5 or 6 superiority dice when they're making so many attacks.
Battlemaster is not a great subclass in terms of combat power IMO.
Battlemaster dice compare well to feats like PAM or Martial Adept. They do not compare well to the better subclass abilities from fighters or to better Feats.
Battlemaster is popular but the fundamental problem at high level is the superiority dice do not keep up with the abilities from the other subclasses. It is a power problem, not a dice problem IMO.