Yet Another question on using GPIO to short a remote push button
CD4066B is one example of a simple quad switch. It has four switches in it which can be controlled independently.

If you drive control signal A, the IC will establish a connection between Pin 1 and 2. Do nce, you can connect two points of earlier switch position to pin 1 and 2 of the IC and control it via CONTROL A signal.
The price is just 13 cents for 1k units.. Or I expect less than a dollar for single IC..
On resistance is 125 ohms but should be okay as long as fast switching isn't needed.
Typical quiescent current is less than 1 uA.
I am just giving one example of such IC and I don't insist to go only for TI IC as such.
Simple way to go if you can buy the ICs.
https://www.ti.com/switches-multiplexers/analog/products.html#p1143=1:1%20SPST
You can explore some more in the above link.