You can review ballistics testing & "real world results" until your eyes cross, and probably without arriving at a definitive "answer".
Suit yourself. Buy the best quality defensive ammunition you can get in good quantities.
I've carried and used either whatever was being issued at the time, or whatever I might decide to buy over-the-counter which I knew would be approved (and I was involved in the 'approval process' for some years). That's included Remington (Express & Golden Sabre), Winchester (T-Series & USA/Duty/Subsonic), Speer (GDHP) and Federal (Hydra-Shok).
I prefer the 230gr standard pressure, but I've also used +P in 185gr, 200gr & 230gr bullet weights. The increased velocity might
be useful if a bullet's nose cavity notching cuts might have been made with a dulling cutter ... and an extra little bit of velocity might help the nose cavity expand ... but it will generate some additional muzzle blast & felt recoil which might adversely impact the shooting abilities of some shooters. Just depends.
Whether the +P ought to be used in a particular make of .45 is something to find out from the gun maker. (You said you owned a G21SF, though, and as an armorer I've never heard Glock recommend against using QUALITY +P in their .45's.) Expect a shorter service life with your recoil spring assembly, though, which isn't unreasonable. Whether you shoot as well with +P is up to you to figure out.
I have the most .45 on hand in Rem GS and Win T-Series (both issued loads in recent years). I'm not overly particular which box is closest at hand when I'm loading magazines and carrying one of my .45's. I also have a fair amount of the old-style USA45JHP 230gr loads, too, but given my druthers I'd prefer to have the more modern hollowpoints loaded with the GS or T-Series bullets. Why not?
I haven't jumped on the band wagon for the HST, myself. Not because I have any issues with the improved starfire-type hollowpoint. I don't. It's just that I don't really care for Federal's late efforts in the way of QC in their pistol ammunition, myself. (Not that other manufacturers don't have their own occasional issues, though.) Besides, Federal just doesn't seem to generate much in the way of LE sales in my area, so I don't see it in working guns as often as the other brands/types. Why go out of my way to try and get it, even if I wanted to use it?
If I couldn't get the T-Series, I'd be completely satisfied with buying either Speer Gold Dot or Rem Golden Sabre, over the counter, and pretty much in that order (and in 230gr). I wouldn't lose all that much sleep if occasionally forced to go back to carrying either of the old style hollowpoints offered in the USA or Express lines, though, either. I just wouldn't expect as consistently robust expansion in some conditions.
Bonded? Well, aside from a major fed user of bonded loads, I've come across far more desire for "bonded" loads on the various public internet gun forums than I've heard among actual LE users. Gold Dot is bonded pretty easily found, if that floats your boat, though. Now that Winchester has released their latest bonded hollowpoint to the public (PDX), you can probably find it around, too ... but it might cost a bit more than the Speer. Dunno. Check for yourself. Me? I don't get too excited worrying about fragmentation or jacket shedding if veh window glass penetration is required. Suit yourself, though. I do.
Sufficient quantities of whatever good quality ammunition is chosen, needed for practice and periodic live-fire function checks in my own
.45's ... accompanied by frequent training/practice and periodic weapon inspection & maintenance. The basics.
The weapon/ammo considerations really take second seat to the awareness, mindset, training/practice and experience issues, anyway, right?
It's just a handgun chambered in one of the common major service/defensive calibers, when it comes right down to it, anyway ...
You have to consistently and accurately hit your intended target for the bullet type to make a difference. First things first.