The term is combining character as opposed to precomposed character. Such superscript combining characters don't exist because subscript or superscript is a formatting feature. Unicode is just a character set for mapping between / to numbers. It only deals with plain text and is not supposed for formatting text

Rich Text. Also known as styled text. The result of adding information to plain text. Examples of information that can be added include font data, color, formatting information, phonetic annotations, interlinear text, and so on. The Unicode Standard does not address the representation of rich text. It is expected that systems and applications will implement proprietary forms of rich text. Some public forms of rich text are available (for example, ODA, HTML, and SGML). When everything except primary content is removed from rich text, only plain text should remain.

(emphasis mine)

You can't make a letter bold, italic or move a letter to above or below the baseline purely with the Unicode code points. Therefore it has no way to format math expressions either (except for very simple ones)

You can find more rationales from the Unicode standard:

Q: What is the difference between “rich text” and “plain text”?

A: Rich text is text with all its formatting information: typeface, point size, weight, kerning, and so on. Plain text is the underlying content stream to which formatting is applied.

One key distinction between the two is that rich text breaks the text up into runs and applies uniform formatting to each run. As such, rich text is inherently stateful. Plain text is not stateful. It should be possible to lose the first half of a block of plain text without any impact on rendering.

Unicode, by design, only deals with plain text. It doesn't provide a generalized solution to rich text issues.

Q: Why doesn't Unicode have a full set of superscripts and subscripts?

A: The superscripted and subscripted characters encoded in Unicode are either compatibility characters encoded for roundtrip conversion of data from legacy standards, or are actually modifier letters used with particular meanings in technical transcriptional systems such as IPA and UPA. Those characters are not intended for general superscripting or subscripting of arbitrary text strings—for such textual effects, you should use text styles or markup in rich text, instead.

Q: I've spotted a sign which uses superscript text for a meaningful abbreviation. Doesn't that mean that all the superscripted letters should be encoded in Unicode?

A: No. It's common for specific formatting to be used to convey some of the semantic content—the meaning—of a text. As for italics, bold, or any other stylistic effect of this sort conveying meaning, the appropriate mechanism to use in such cases is style or markup in rich text.

https://www.unicode.org/faq/ligature_digraph.html

That means you must use a math rendering tool like LaTeX, MS Equation Editor, MathType, MathML... One the simplest math renderers if you don't like LaTex is AsciiMath, but typically LaTeX is the "standard"