Can a low concentration of an acid disolve solids just as well?
The rate of dissolution depends on $\mathrm{pH}$ and $\mathrm{pH}$ dependent equilibrium reaction chain :

$$\begin{align}
\ce{2 CH3COOH + CaCO3 v &amp;&lt;=&gt; (CH3COO)2Ca + Ca(HCO3)2}\\
\ce{2 CH3COOH + Ca(HCO3)2 &amp;&lt;=&gt; (CH3COO)2Ca + 2 H2CO3}\\
\ce{H2CO3 &amp;&lt;=&gt;   H2O + CO2(aq)}\\
\ce{CO2(aq) &amp;&lt;=&gt;   CO2(g)}\\
\end{align}$$

what can be written in the equivalent ionic form:

$$\begin{align}
\ce{CaCO3 v &amp;&lt;=&gt; Ca^2+ + CO3^2-}\\
\ce{CH3COOH &amp;&lt;=&gt; CH3COO-  + H+}\\
\ce{H+ + CO3^2- &amp;&lt;=&gt; HCO3-}\\
\ce{HCO3-  + H+ &amp;&lt;=&gt; H2CO3}\\
\ce{H2CO3 &amp;&lt;=&gt;   H2O + CO2(aq)}\\
\ce{CO2(aq) &amp;&lt;=&gt;   CO2(g)}\\
\end{align}$$

6% vinegar (1M) acetic acid has $\mathrm{pH=p}K_{\mathrm{a}}/2=2.37$.

Vinegar with 1/11 acid  spent has pH 3.75, with activity of $\ce{H2O+}$  24 times lower, so does is lower the reaction speed.

Vinegar with the acid half spent has pH 4.75, with activity of $\ce{H2O+}$ 240 times lower.

Vinegar with 10/11 acid  spent has pH 5.75, with activity of $\ce{H2O+}$  2400 times lower.

If pH raises enough, equilibrium concentration of $\ce{CO2(aq)}$ does not cross the gas solubility limit anymore and reaction approaches equilibrium, as production of gaseous carbon dioxide ceases..

If initial concentration crosses some minimal threshold, $\mathrm{pH}$ raises to level not able to produce gaseous carbon dioxide before water gets saturated by $\ce{CO2}$.

Some carbonate gets dissolved as bicarbonate, but with low initial acetic acid concentration, this dissolution is slow.

See also carbonic acid Wikipedia article.

Another effect is diffusion limitation. Without stirring, the acid near walls may get spent, while the acid abundance in free volume is intact, without access to limescale. Rate of acid diffusion to walls limits rate of dissolution.

Personally I would suggest rather citric acid, that have much higher acidity.

And/or, instead of filling the whole volume by diluted solution , rather using wall washing by concentrated solution.