To do some wiring that'll be bulletproof and last:
1. get wiring rated for under-the-hood heat (the wiring sold at auto parts stores is no good for that)
2. get crimp-on connectors
3. cut the plastic off the crimp-ons
4. put heat shrink tubing on the wire, well away from the end
5. crimp the connector on
6. solder the crimp joint using a thermostat controlled soldering iron
7. move the heat shrink tubing over the joint, and heat it with a bic cigarette lighter to shrink it on
8. voila!
P.S. Crimped connections don't last. After about a year, they'll work loose a bit from vibration, and corrosion will creep in, and you'll get a loose connection that is very frustrating to find. Soldering it prevents that from happening.
You're right about not letting the solder wick up past the connector. But that's not an issue if the wire is properly supported with a clamp.
My experience with crimps is electrical gremlins, with soldered crimps, no trouble at all.
OEM crimps also come with a molded housing designed to keep out moisture (and corrosion) and provide mechanical support for the joint. The crimp-on connectors at the auto parts store are vastly inferior.
That's called a crimping tool. They grow on trees. They're designed to achieve the correct amount of force to make a gas tight, permanent connection without destroying the contacts. All you need to do is select the correct connectors for the wire size you're dealing with and squeeze it.
I watched a professional cable installer once crimp the coax F connectors on. I got the manufacturer and model number of it. It's from an outfit that only sold to professionals, and cost about $200. Since I was going to pull all the coax myself in my house, it was worth the money and I haven't had trouble with the results. The consumer grade crimping tools from the hardware store are terrible.
It's the same story with wirewrap tools.
Take a look at these:
https://www.amazon.com/Qibaok-Connectors-Insulated-Electrica...
Crimp a wire in it. Look at it from the connector side. You'll see the bare conductor inside the connector. That's where the moisture gets in. Heat shrink tubing won't shrink enough to cover that. Wicking solder into it will seal it against moisture and corrosion.
Never had trouble with the completed soldered/crimped connections for decades. I use them in my car. With crimp-only, it's only a matter of time till I get erratic connects. It's particularly irritating with the stereo, as the speakers go in and out or suffer the crackling with a loose connection.
Interestingly, the speaker cable connections in the house are a nuisance with bad connections. Spring loaded connectors, even banana plugs, are just plain unreliable. Solder finally fixed them for good. (I'll solder on connectors, and then use a terminal strip.)
For the car, I also use rather expensive high grade stranded wire. I've been very happy with the results - the extra money pays off in time saved not having to repair them.
Solder will fill any voids in your contact, causing the bond to break as your entire assembly heats and cools.
Solder will also wick up the strands, making the resultant wire brittle.
Moisture ingress can be solved with the correct wrapping. After all, the extruded PVC insulation on the wire in the first place shrunk to fit it, right?
https://www.amazon.com/JRready-Connector-Waterproof-Electric...
The cheaper knock offs can work well, too.
I have electronic equipment in nearly continuous use for 40 years. Daily heat/cool cycling. No solder breaks in it.
It seems that this debate is an old one:
https://www.linkedin.com/advice/0/what-pros-cons-soldering-v...
https://blog.peigenesis.com/soldering-vs-crimping-advantages...
https://www.sig4cai.com/soldering-or-crimping-which-is-bette...
P.S. I'm pretty good with soldering, since I've done it professionally, so the disadvantages of a poorly soldered joint don't apply.
My crimped and soldered ones work fine, though, and cost basically nothing.
I've studied this a little since it effects my work, but I don't claim to be an EE. Sadly, I'm not finding any definitive authorities on the subject with a quick googling, though all the top hits tend to agree with the sentiment of not soldering crimped connections.
This was a short article that I ran across, dealing with the topic. As usual, the comments on hackaday are all over the place, but I still find them useful.
https://hackaday.com/2017/02/09/good-in-a-pinch-the-physics-...
Interestingly, I thought nasa banned soldering crimped connections, but as far as I can tell, rereading this doc now with a quick skim for the string crimp, they only ban crimping tinned connections.
https://s3vi.ndc.nasa.gov/ssri-kb/static/resources/nasa-std-...