A couple tips from another amateur:
- Twist those wire ends before doing anything. You want a good spiral on them with all of the strands together.
- With the wires well twisted, tin them. This means hold the iron against the wire end to get it hot and let solder flow over the wire. The wire end should then look like it's coated in solder. There are a lot of videos on it, search for "tinning wire".
- Keep practicing, it gets easier.
It depends on what your goals are.
Ultimately, it's going to come down to what you are trying to do and why you want to run multiple Operating Systems. For example, my main system is running Linux. But, I want the ability to run Windows malware in a controlled sandbox (not a euphemism, I work in cybersecurity and lab some stuff for fun). So, I have KVM setup to run Virtual Machines, including Windows.
For another example, prior to making the switch to Linux, I had Windows as my primary OS and booted Linux on a USB stick (not Ventoy, but close enough). This let me gain confidence that I would be able to make the jump.
I don't have a good example for dual booting. Maybe something like a SteamDeck where you want a stable, functional OS most of the time; but, have some games which will only run in Windows.