Not watching, but Kuhl looks like he is turning in a fantastic start. There might be something to letting him ride things out with a few more September starts - it's not like anything matters. I do feel like over the course of the season, he's shown to be more of a #5 type, without significantly more upside, and so with the pitcher jam, it makes sense to deploy him as a dominant backend of the bullpen guy. Still, in fairness he has certainly turned in some impressive starts, and neither him being good in the back of the bullpen, or another starter even replicating his season from this year are foregone conclusions.
Brault is starting tomorrow, and surprisingly it's the first lefty all season getting a start. He has not been impressive in the bit that I've seen of him in MLB this year, but between his AAA season and his makeup, he's definitely someone we should see 4-5 times this month so that we can get some sense heading into next year.
Glasnow obviously too, but I almost think it's better to handle him with some caution, maybe getting him 2-3 starts and hoping he does well, to keep the season ending on a high note. Not that he should be babied, but he's done well to turn it around and get some momentum, and he's already at a career high for innings. Brault certainly has a lower ceiling, but there aren't a ton of starts to even go around, and he's earned something of a look for his AAA performance. I'd probably rather see Kingham a few times than see Glasnow in meaningless games at the end of the season. It's not too complicated with him - he has either figured out how to harness his pitches and repeat his delivery, in which case he will be an impressive rookie, or else he will go back to maddening inconsistency, prompting a bullpen decision perhaps. Neither of those options are going to be cemented by a couple meaningless September starts, and in any case, maybe better to have him hungry in camp again.