Some general remarks may help already: One way is to press the physical button "GEQ" on your board (right above the master fader). The mixer's menue now shows everything you need to tweak. "EQ Status" is third in the row. The second way is (in UC Surface) to press "GEQ" on the flex channel. You find the on/off button on the very left side. So first check in all output channels, if the GEQ's are switched on!
Not hearing changes of the GEQ may have the reason that you are not listening at the right point in the chain. GEQ's only work on the physical outputs, but not on the headphone out. I would need to read it in the manual again, but I think that GEQ in "Main" also does not affect the Control Room outputs.
In AVB "stagebox mode" the RM32AI's processing is not working at all - or better said: All outputs are bypassed and represent your SL 3242AI's output (Aux 15 and 16 are your subgroups 1+2). Only in AVB "I/O mode" you can use all processing on the 16 mix outs (including GEQ's), but not the main output, which is handled by the SL 3242AI's GEQ.
"Main GEQ" on a stand-alone RM32AI also handles its "mono" output, so there are actually 3 separate graphic equalizers working. Of course you can not hear any changes of your PA's GEQ if you are tweaking the mono out's GEQ... Always watch out the two virtual buttons (Main|Mono) right under the faders!