Basic implementation
After working on this answer, I realized that the undocumented FrontEnd`ExportPacket with "InputForm" as second argument may be considered as an alternative to FullGraphics. First, a basic definition:
fullGraphicsBasic[expr_, dist_ : 1.2] := Block[{e = dist}, ToExpression[ First@FrontEndExecute[ FrontEnd`ExportPacket[Cell[BoxData@ToBoxes[expr]], "InputForm"]]]]
Here is a demonstration of how fullGraphicsBasic works (Mathematica 13.1.0):
Plot[Sin[x], {x, 0, 6 Pi}] fullGraphicsBasic[%] ResourceFunction["ShortInputForm"][%]



The axes and ticks look lighter than they are on the original figure due to the default Antialiasing -> True applied to the graphics primitives (by default Axes and Frame are rendered with Antialiasing -> False). We can fix this, for example, as follows:
fullGraphicsBasic[Plot[Sin[x], {x, 0, 6 Pi}]] /. AbsoluteThickness[0.2`] :> Sequence[AbsoluteThickness[0.2`], Antialiasing -> False]

Discussion and better implementation
I was forced to wrap the main code of fullGraphicsBasic with Block, because for some reason it returns an expression with undefined variable e, which determines the distance between the minus sign and the number. The minus signs are separately drawn as Style["-", FontFamily -> "MathematicaSans"], while the numbers are drawn with FontFamily -> "Arial". Surprisingly, the "Hyphen-Minus" characters "-" look the same (at least on Windows 10 x64) in these fonts, so this complication is completely redundant. But it makes a trouble, because the correct value for this variable seemingly depends on where the number is placed on the plot. The same problem applies to some other mathematical characters, for example: ~, ±, = etc. Applying PrivateFontOptions -> {"OperatorSubstitution" -> False} doesn't change this behavior.
This feature/bug is present in all versions I checked: 8.0.4, 12.3.1 and 13.1.0, excepting version 5.2 where the method itself doesn't quite work. It is interesting, that if I specify "Output" as a style for the Cell in the definition above, this undefined variable e disappears and the result looks as if it is replaced with 1.8 (as a consequence, the minus sign runs over the number). These observations indicate that this functionality of FrontEnd`ExportPacket is still incomplete.
As a workaround to this horrible feature, one can replace the "Hyphen-Minus" character with zero before applying FrontEnd`ExportPacket, and then replace it back after it. Since we are most interested in reproducing the Ticks and FrameTicks, we can proceed as follows:
Clear[fullGraphics] fullGraphics[expr_] := Module[{e}, e = expr /. g_Graphics :> Show[g, AbsoluteOptions[g, {Ticks, FrameTicks}] /. s_String :> StringReplace[ s, {StartOfString ~~ "-." -> "00.", StartOfString ~~ "-" -> "0"}]]; ToExpression[ First@FrontEndExecute[ FrontEnd`ExportPacket[Cell[BoxData@ToBoxes[e]], "InputForm"]]] /. Text[Style[s_String, opts__], c__] :> Text[Style[Row[{Invisible["0"], StringReplace[ s, {StartOfString ~~ "0" ~~ d : DigitCharacter :> "\[Minus]" <> d}]}], opts], c]];
Plot[Sin[x], {x, 0, 10}] /. {HoldPattern[Frame -> _] -> Frame -> False} // FullGraphics$\endgroup$