Confused about the gain effect over cutoff frequency
Assume that everything is ideal LTI ZIC.
Try to derive the transfer function first to understand it.
Hint: Remember the golden rule of op amp and use nodal analysis at the input terminal of it.


The result will be like this:

Ideal second-order LPF LTI ZIC (such as series RLC) will have prototype transfer function like this:


The G factor doesn't change the pole frequency (natural
frequency). Even though that's true, it still change most of the filter characteristics, which we usually design using known topology (such as Butterworth, Chebyshev, …). It changes asymptotic gain (of course), 3dB cut-off frequency, bandwidth, the damping ratio/quality factor, thus the phase margin or stability and so on.
Both of the circuit natural frequency is 53.636
rad/s, thus the pole frequency at 8.53 Hz.

Now lets try to take a look at the characteristics equation of the pole. By
Descartes' rule of signs, at least one sign changes of the term
will results in positive roots, thus instabilities. We need to make
sure that all of the terms have the same sign.
The only possible term is on the middle one because there is a subtraction of \$1 - G\$. And we don't want the second term to be zero, it would be an oscillator, so it must be strictly positive.
\$ \frac{1}{C1R2} + \frac{1}{C1R1} + \frac{1}{C2R2}(1-G) \gt 0 \$
\$ \frac{1}{C1R2} + \frac{1}{C1R1} + \frac{1}{C2R2} \gt \frac{1}{C2R2} G \$
\$ \frac{C2}{C1} + \frac{C2R2}{C1R1} + 1 \gt G \$
\$ \frac{C2}{C1} \left( 1 + \frac{R2}{R1} \right) + 1 \gt G \$
In both of your circuit you have
\$ \frac{1u}{10u} \cdot \left(1 + \frac{31.6k}{1.1k} \right) + 1 = 3.9\overline{72} \$
While you have G factor of 6 on the first circuit and 11 on the second one. This indicates that both of the circuits is unstable. No wonder in the bode plot, at infinite frequency you get phase lead of +180 degrees instead of the correct phase lag of -180 degrees.
G factor needs to be less than \$3.9\overline{72}\$ in order for the circuit to be stable. R3 in your circuit (in mine is R4) must be no more than \$59454.5\ \Omega\$.



My favorite site to simulate ideal Sallen-Key filter:
http://sim.okawa-denshi.jp/en/OPseikiLowkeisan.htm