They seem to be working after changing the devanagari font to Noto Sans Kaithi but only for one digit though, also they do not appear when alone.
Since the kaithi unicode does not have its own numerals and uses the devanagari ones, is there any way to only change the devanagari font when it is near the kaithi number signs?

Here is the Text I entered, sorry for not including them earlier, I thought that mentioning their codepoints should be enough.
KAITHI NUMBER SIGN: 𑂽
KAITHI NUMBER SIGN + DEVANAGARI 0: 𑂽१

KAITHI NUMBER SIGN ABOVE: 𑃍
KAITHI NUMBER SIGN ABOVE + DEVANAGARI 0: 𑃍०

On Fri, Apr 29, 2022 at 4:20 PM Eli Zaretskii <eliz@gnu.org> wrote:
> From: समीर सिंह Sameer Singh <lumarzeli30@gmail.com>
> Date: Fri, 29 Apr 2022 15:15:41 +0530
> Cc: emacs-devel@gnu.org
>
> I did the changes mentioned.
> 1. Added the square brackets
> 2. Changed the 1 to a 0
>
> ;; Kaithi composition rules
> (let ((consonant "[\x1108D-\x110AF]")
>       (non-consonant "[^\x1108D-\x110AF\x110B9]")
>       (vowel "[\x110B0-\x110B8\x110C2]")
>       (anusvara-candrabindu "[\x11080\x11081]")
>       (virama "\x110B9")
>       (number-sign "\x110BD")
>       (number-sign-above "\x110CD")
>       (numerals "[\x966-\x96F]"))
>   (set-char-table-range composition-function-table
>                         '(#x110B0 . #x110B8)
>                         (list (vector
>                                (concat consonant vowel anusvara-candrabindu "?")
>                                1 'font-shape-gstring)))
>   (set-char-table-range composition-function-table
>                         '(#x110B9 . #x110B9)
>                         (list (vector
>                                (concat consonant "\\(?:" virama consonant "\\)+"
>                                        vowel "*\\|" consonant virama)
>                                1 'font-shape-gstring)))
>   (set-char-table-range composition-function-table
>                         '(#x110BD . #x110BD)
>                         (list (vector
>                                (concat number-sign numerals)
>                                0 'font-shape-gstring)))
>   (set-char-table-range composition-function-table
>                         '(#x110CD . #x110CD)
>                         (list (vector
>                                (concat number-sign-above numerals)
>                                0 'font-shape-gstring))))
>
> Now when typed alone they do not appear but when written with numbers, they appear as NOTDEF glyphs

Are you sure the font supports all of those characters?  What font is
used for them in each case.

And again, you don't show the text that doesn't render correctly (as
characters), so it's impossible to investigate the cases you tried.
Images help to see how stuff is displayed, but they cannot be used to
reliably figure out what text was displayed.  I asked you to show the
actual text many times.