Modern D&D is really a miniatures game (WoTC's bottom line really wants it to be a miniatures game), and as such basic "you go I go" combat is a complete waste of time in it. Skip the first few levels and only bother running encounters where positioning, AoE and range actually matter. Sure, you might throw a generic wild animal encounter in with a beginner group to teach them how the basics of combat work, but that's the sort of thing you run at most once with each group.

> Modern D&D is really a miniatures game

No more than that has been true of every version of D&D, and its immediate predecessor Chainmail, with the possible exception of the B/X / BECMI / Rules Cyclopedia versions that existed as a lighter version in parallel to AD&D1 & AD&D2.

Modern D&D is, perhaps, a miniatures game targeting comparative casual modern players, but OD&D/AD&D1 was definitely a miniatures game targeting the tastes of comparatively obsessive, high-rules-focus 1970s-1980s tabletop wargamers, with a light dusting of RP on top. Heck, much of the rules were specified in terms of scale distance for miniatures (inches on the tabletop).

I run a complete home brew system. I just keep max health low and combat potential low. Every time you receive an injury you suffer a noteworthy injury, die, or start dying. A random human with a knife should always be threatening… because it is. A guy with a knife is actually really scary. A guy with a gun even more so.

With such a system you tend not to have any meaningless fights, and when you do, you make it zany and high stakes and expect at least one person to suffer a severe injury or die.

Older D&D editions specifically made combat much deadlier and incentivized players to avoid combat or use out-of-combat advantages as much as possible for this reason. Modern D&D caters to a crowd that enjoys metagaming and minmaxing combat more.

> Older D&D editions specifically made combat much deadlier

That’s not really true, IMO; older D&D made combat harder to calibrate to the desired level of deadliness because there were more irresistible forces and unmovable objects. Modern D&D is much easier to tune to the precise preferred deadliness. That’s pretty much a monotonic progression across the history of D&D. (Ignoring the boxed set series and considering just OD&D -> AD&D1 -> AD&D2 D&D/3/3.5/4/5, and leaving out the in-playtest One because I haven’t really checked any of the material out.)

> Modern D&D caters to a crowd that enjoys metagaming and minmaxing combat more.

IME and IMO, 4e was a local peak of that, but not more than either AD&D1 or AD&D2, especially the late era of the latter. Heck, in AD&D1 its was common for people who didn’t want the game to be dominated by the metagame to slice out big chunks that were oriented toward that (most notoriously, the weapon to-hit vs. armor class type system).

> Boring to play too. I’m wondering how chatGPT, or other such aides can be used to make combat better.

You could just use a TTRPG with better combat for your tastes; it doesn’t take AI (OTOH, an AI with information on enough different games and how they play might be able to interview you to find a good choice, or even custom mix and match pieces to make a unique game optimized for your individual tastes – or that of a group.) If you don’t like D&D combat, there are lots of other models.

I knew I’d like RuneQuest when the DM said “roll a hit location.”