When I was in my early 20's and had just a few handguns, there were "gaps".
Now I am in my early 50's and have dozens of handguns; there are still "gaps".
To me, looking back, there are two questions: Where are your gaps? Are the handguns you have outstanding for you?
If you don't have a medium-caliber SD handgun, there is a gap. If you don't have a 22 handgun there is a gap. If you don't have a large-caliber handgun, there is a gap. If you don't have a semi-automatic and a revolver in each category, there is a gap. If you don't have a SA and a DA revolver, AND a DA and SA semi-automatic pistol in each category, there is a gap. And so on and so forth. It never ends.
On the other side of things, I adore my CZ75 clone. I already owned four or five 9mm pistols when I bought it; there were no gaps. But after I bought it all of my other 9mm's were second-tier.
That being said...
I have a Mosquito. It is not good. My Browning Buck Mark and my friend's Ruger Mark II target model put it into the shameful category. If you have never owned a fine 22 pistol, you've never really owned one (and a good used one is not that expensive).
Outstanding DA 22 revolvers are not necessarily cheap or easy to come by. I own one of the Taurus Trackers that you mentioned. Its DA trigger is bad. Other than that it is a very good revolver - its SA trigger is decent and it is extremely accurate & reliable. I have owned a lot of DA 22 revolvers. Most of them have bad DA triggers. It is apparently difficult to make a DA 22 revolver that will reliably ignite the rimfire ammunition, and will also have a nice DA trigger. In SA revolvers, it is apparently much easier. I have yet to find a DA revolver that I would prefer to my Single Six. Its SA trigger is sweet and it is more accurate than I am. My Single Six is not for SD. It is for targets or plinking or small game. I do not need to reload it quickly, and drawing the hammer back between shots doesn't interfere with anything.
I consider my medium-caliber handguns to be my bread-and-butter for SD, hunting... and plinking or target-shooting if I want something other than a 22. If I didn't have a medium-caliber revolver and/or semi-automatic pistol that had a great trigger, and was very accurate and reliable, I would consider myself to have a HUGE gap somewhere. "Okay" is not good enough. My best in each category (SA revolver, DA revolver, SA pistol, DA pistol) are so extremely good that all of the rest are superfluous. I also CC, so I want at least one good small & light CC medium-sized caliber revolver, and one good small & light medium-caliber pistol as well.
For me, larger-caliber revolvers and pistols are for fun. I am in no danger of being attacked by bears or giants, but I like the big noise and recoil and like putting big holes in things, or blowing them completely apart. It is fun! I am happy to have revolvers and pistols and these kinds of calibers because I enjoy them. I didn't have a 1911 for a long time. Now I have four. They are excellent pistols.
I think you pretty much either like SA revolvers or you don't. For SD I will take DA every time. Otherwise I prefer the SA. I am not in a hurry if I am shooting targets or plinking or hunting small game (easy high-percentage shots). I like the feel of their SA triggers, and the plowhandle grip works better for me. I have revolvers I prefer for SD in all of the small-medium-and-large-caliber categories, but for general shooting I prefer my SA revolvers. Everyone is different as far as that goes.
Sorry for the wall of text.