Tag Difference: ID3v2.3 vs. ID3v2.4

[MP3Freak_Peter]

Is it smart to batch convert my library to 2.4?

no, cause 2.3 is - as you wrote - more common.
You'll get more problems than advantages.

An older thread (now: ID3v2.3 UTF-16 is supported by most players)

What ID3v2 tag to use?

Just keep the standard settings (v2.3 utf-16) if you have no troubles with them.

Or that one

ID3v2.5 or ID3v3

The development of the ID3 tag format seems to have stalled if not ceased altogether, not least because most new downloads and rips use other container formats than MP3, notably ISO MPEG 4 part 14 (MP4/MOV) and Matroska (MKV), which come with their own metadata formats, although an ID3v2 tag may be embedded as well. However, I think there would still be some merit in updating ID3. For instance, neither the official site nor the Github repository documents all the predefined v1 genres actually s…

The explaination of 2.3 vs 2.4 is very coding-like explanation.
Would really appreciate if someone could explain it simply but both comprehensive and extensive.

Sorry, I can't.
But you can have a look here : https://id3.org/