Op-amp input impedance
In addition to the other comments and answers you've received, take a look at Figure 5 on this webpage:

https://masteringelectronicsdesign.com/buildi-an-op-amp-spice-model-from-its-datasheet/

Figure 5 doesn't show the current sources IB+ and IB+ but its resistors Rin1 and Rin2 correspond to Zcm+ and Zcm-, respectively, and its resistor Rin corresponds to Zdiff.  Redrawing Figure 5 with an emphasis on the op amp's amplifier+output stage (the dependent voltage-controlled voltage source VCVS) and negative feedback path yields the schematic below.







simulate this circuit &ndash; Schematic created using CircuitLab

Note that resistor \$R_2\$ is in parallel with the op amp's input impedances \$R_{\text{in2}}\$, \$R_{\text{in}}\$, \$R_{\text{in1}}\$, etc., and when \$R_2\$'s value is much less than the op amp's input impedance we have:

$$
R_2\;||\;(R_{\text{in2}}, R_{\text{in}}, R_{\text{in1}}, ...) \approx R_2
$$

Also note that VCVS and the op amp's "bias current" IB (not shown) both influence the voltage potential at the op amp's inverting input. When R2's resistance is small compared to the op amp's input impedance, IB's influence at the inverting input is "swamped out" by VCVS, R1, and R2.

$$
V_{\text{IN-}} \approx \text{VCVS} \frac {R_2\,||\,(R_{\text{in2}},R_{\text{in}},R_{\text{in1}},...)}{R_{\text{out}} + R_1 + (R_2\,||\,(R_{\text{in2}},R_{\text{in}},R_{\text{in1}},...))} \bigg\rvert_{R_2 \lll (R_{\text{in2}},R_{\text{in}},R_{\text{in1}},...)}
\\
\Rightarrow 
V_{\text{IN-}} \approx \text{VCVS} \frac {R_2}{R_{\text{out}} + R_1 + R_2}
$$

For what it's worth, that Analog Devices MT-040 data sheet doesn't clearly define or give typical values for the "bias currents" IB- and IB+, which only creates confusion.  Assuming IB is the very tiny reverse leakage current (on the order of nanoamps) that flows through the reverse biased collector-base diodes of the two BJTs whose bases are connected to the inverting (IB-) and non-inverting (IB+) inputs, that IB current is so tiny that VCVS, R1, and R2 can easily dominate the voltage potential at the op amp's inverting input if R2's resistance value is much less than the op amp's input impedance.  For example, add an independent current source at node IN- (the op amp's inverting input) whose amperage is, say, 10&nbsp;nA, and see what effect it has on the voltage potential at IN-.