Erdős problem 848

Is the maximum size of a set $A ⊆ \{1, \dots, N\}$ such that $ab + 1$ is never squarefree (for all $a, b ∈ A$) achieved by taking those $n ≡ 7 \pmod{25}$?

This asks whether Erdos848 N holds for all $N$ (formulated using A ⊆ Finset.range N).

This was solved for all sufficiently large $N$ by Sawhney in this note. In fact, Sawhney proves something slightly stronger, that there exists some constant $c>0$ such that if $\lvert A\rvert \geq (\frac{1}{25}-c)N$ and $N$ is large then $A$ is contained in either $\{ n\equiv 7\pmod{25}\}$ or $\{n\equiv 18\pmod{25}\}$.