Answering Q1.
One has
$$
\sum_{n=3}^{\infty}\ln\!\Big(1+\frac1{2n}\Big) \!\ln \!\left(\!\frac{2n^2+n-6}{2n^2+n-10}\!\right)=\ln\!\Big(\frac32\Big) \!\ln \!\Big(\frac76\Big)+\ln\!\Big(\frac54\Big) \!\ln \!\Big(\frac98\Big). \tag1
$$
Proof. One may write
$$
\begin{align}
&\sum_{n=3}^{\infty}\ln\!\Big(1+\frac1{2n}\Big) \!\ln \!\left(\!\frac{2n^2+n-6}{2n^2+n-10}\!\right)
\\=&\sum_{n=3}^{\infty}\ln\!\Big(1+\frac1{2n}\Big) \!\ln \left[\frac{(2n-3)(n+2)}{(2n+5)(n-2)}\right]
\\=&\sum_{n=3}^{\infty}\ln\!\Big(1+\frac1{2n}\Big) \!\ln \!\left[\frac{(2n-3)(2n+4)}{(2n+5)(2n-4)}\right]
\\=&\sum_{n=3}^{\infty}\ln\!\Big(1+\frac1{2n}\Big) \!\left[\ln \!\left(\frac{2n-3}{2n-4}\right)-\ln\left(\frac{2n+5}{2n+4}\right)\right]
\\=&\sum_{n=3}^{\infty}\ln\!\Big(1+\frac1{2n}\Big) \!\left[\ln \!\left(1+\frac{1}{2(n-2)}\right)-\ln\left(1+\frac{1}{2(n+2)}\right)\right]
\\=&\sum_{n=3}^{\infty}\ln\!\Big(1+\frac1{2n}\Big) \!\ln \!\left(1+\frac{1}{2(n-2)}\right)-\sum_{n=3}^{\infty}\ln\!\Big(1+\frac1{2n}\Big)\ln\left(1+\frac{1}{2(n+2)}\right)
\\=&\sum_{\color{red}{n=1}}^{\infty}\ln\!\Big(1+\frac1{2(n+2)}\Big) \!\ln \!\left(1+\frac{1}{2n}\right)-\sum_{\color{blue}{n=3}}^{\infty}\ln\!\Big(1+\frac1{2n}\Big)\ln\left(1+\frac{1}{2(n+2)}\right)
\\=&\ln\!\Big(\frac32\Big) \!\ln \!\Big(\frac76\Big)+\ln\!\Big(\frac54\Big) \!\ln \!\Big(\frac98\Big),
\end{align}
$$ where we have made a change of index.
Similarly, one has
$$
\sum_{n=3}^{\infty}(-1)^n\ln\!\Big(1+\frac1{2n}\Big) \!\ln \!\left(\!\frac{2n^2+n-6}{2n^2+n-10}\!\right)=\ln\!\Big(\frac54\Big) \!\ln \!\Big(\frac98\Big)-\ln\!\Big(\frac32\Big) \!\ln \!\Big(\frac76\Big). \tag2
$$
Proof. One may write
$$
\begin{align}
&\sum_{n=3}^{\infty}(-1)^n\ln\!\Big(1+\frac1{2n}\Big) \!\ln \!\left(\!\frac{2n^2+n-6}{2n^2+n-10}\!\right)
\\=&\sum_{n=3}^{\infty}(-1)^n\ln\!\Big(1+\frac1{2n}\Big) \!\ln \left[\frac{(2n-3)(n+2)}{(2n+5)(n-2)}\right]
\\=&\sum_{n=3}^{\infty}(-1)^n\ln\!\Big(1+\frac1{2n}\Big) \!\ln \!\left[\frac{(2n-3)(2n+4)}{(2n+5)(2n-4)}\right]
\\=&\sum_{n=3}^{\infty}(-1)^n\ln\!\Big(1+\frac1{2n}\Big) \!\left[\ln \!\left(\frac{2n-3}{2n-4}\right)-\ln\left(\frac{2n+5}{2n+4}\right)\right]
\\=&\sum_{n=3}^{\infty}(-1)^n\ln\!\Big(1+\frac1{2n}\Big) \!\left[\ln \!\left(1+\frac{1}{2(n-2)}\right)-\ln\left(1+\frac{1}{2(n+2)}\right)\right]
\\=&\sum_{n=3}^{\infty}(-1)^n\ln\!\Big(1+\frac1{2n}\Big) \!\ln \!\left(1+\frac{1}{2(n-2)}\right)-\sum_{n=3}^{\infty}(-1)^n\ln\!\Big(1+\frac1{2n}\Big)\ln\left(1+\frac{1}{2(n+2)}\right)
\\=&\sum_{\color{red}{n=1}}^{\infty}(-1)^{n+\color{red}{2}}\ln\!\left(1+\frac1{2(n+2)}\right) \!\ln \!\left(1+\frac{1}{2n}\right)-\sum_{\color{blue}{n=3}}^{\infty}(-1)^n\ln\!\left(1+\frac1{2n}\right)\ln\left(1+\frac{1}{2(n+2)}\right)
\\=&-\ln\!\Big(\frac32\Big) \!\ln \!\Big(\frac76\Big)+\ln\!\Big(\frac54\Big) \!\ln \!\Big(\frac98\Big),
\end{align}
$$ where we have made a change of index.
Answering Q2.
The given series are just an instance ($k=1$) of the following family.
Proposition. Let $k=1,2,3,\cdots.$ Then
$$
\begin{align}
{\small \sum_{n=2k+1}^{\infty}}&{\small \ln\!\left(\!1+\frac1{2n}\!\right) \!\ln \!\left(\!\frac{2n^2+n-8k^2+2k}{2n^2+n-8k^2-2k}\!\right)=\sum_{n=1}^{2k}\ln\!\left(\!1+\frac1{2n}\!\right) \!\ln\!\left(\!1+\frac1{2n+4k}\!\right)}, \tag3
\\\\
{\small \sum_{n=2k+1}^{\infty}(-1)^n} &{\small \ln\!\left(\!1+\frac1{2n}\!\right) \!\ln \!\left(\!\frac{2n^2+n-8k^2+2k}{2n^2+n-8k^2-2k}\!\right)=\sum_{n=1}^{2k}(-1)^n\ln\!\left(\!1+\frac1{2n}\!\right) \!\ln\!\left(\!1+\frac1{2n+4k}\!\right)}. \tag4
\end{align}
$$