Best settings for PNG Conversion

[Messiah]

Greetings, I have many personal pictures, images and such with a lossy format such as jpg. And here I want to convert everything (easily +10k files) for the best format possible when it comes to keep the quality from degrading, so as PNG.

Felt that XnConvert is really a good software, simple looking but truly useful with many features. Same as all the XnView produced softwares to be honest, really thank's for all your hard works!

Well, to get the main point. I wish to know the correct way to do it for best results without messing up. I'm also worried if there are settings activated per default that may affect my initial purpose, since I'm going to delete the old files after converting everything, even saw there is already an option for that.
Knowing what I want to do, what can you advice me for settings like *Compression level, Interlacing, and there are things that I didn't get well like Multipage, Preserve color profile and Filters.

Finally, is it worth converting everything to PNG? What about personal pictures? I've read in many topics that it depends and there may be some lose in many other ways... Is JPG really that bad? What the worst that may happens with it and how to avoid it?

[xnview]

PNG is good for lossy, but compress (int size) not always very well...

'Compression level' depends on image that you save.
Interlacing is only for web so no need in your case.