Music video on Youtube → Record video and sound simultaneously or separately?

Would like to start a YouTube channel with my own music videos.
Now my question: I'm familiar with filming / editing etc. Unfortunately not at all. Is it better to record video and sound at the same time (i.e. Micro to the camera and record) or to record the audio separately with a music program on the laptop and add it to the video (I'm afraid that it will not be completely synchronized)?

Have a Sony A58 (SLR), if that helps.

If music program, can you recommend one for Windows / Android?

Is that a video camera? If so, I would first record the sound with the camera and practice editing etc. Of course, adding the sound later has the advantage that the sound quality is usually better. I do not know how to change it if it is not completely synchronous, but there are certainly technical possibilities.

Professionals naturally record the picture and sound separately and also use a film flap for this:

https://de.wikipedia.org/...Filmklappe

This also synchronizes the video.

With Audacity you can record and edit: https://www.audacity.de/erste-schritte/

For the synchronization you can clap your hands loudly in the video, it has the same purpose as a clapperboard. The audio track is based on this.

For the start, I would just keep it simple and record everything together with one device (if nothing speaks against it like with my DSLR where you hear noises in the video during autofocus).

Learning, trying and growing with it comes with time.

If you want to make music videos, what kind of sound do you want to record? The sound (the music) is already finished.

It would be even better to record everything on the PC right away, I think. So record camera in WebCAM mode and sound via an audio interface and both in the editing program.