A CB has buttons for NB and ANL. Most ham rigs have IPO, ATT, AGC, NB, DNR, Notch Filters, IF Shift, and more and most are adjustable. I basically understand what each does (except for AGC) and want to know, "Are you guys constantly pushing buttons and twisting knobs?" It was all very overwhelming to me and one of the main reasons I raised the white flag.
IPO is just a marketing name for "RF preamplifier". Some brand purists will argue the point, but that is what it is. I rarely engage the RF preamp until I get above 20m.
ATT is the RF attenuator which helps to keep the receiver from overloading especially on the lower bands with stronger signals. I usually have the ATT enabled on 160, 80, and 40m. If you can still hear band noise with it enabled, it's a good idea to use it.
AGC is the Automatic Gain Control which is circuitry that attempts to present a constant audio level to the speaker over a wide range of received signal strength. Some radios only offer fast and slow AGC control. Others have a third position and still others are adjustable. CW operators often like a fast AGC and phone ops a slow AGC which prevents the noise level from rising in between syllables and such. On my FT-890 I prefer the fast AGC even on phone and would like an even faster AGC for CW. Some radios allow for turning the AGC off which is interesting. Be prepared to work the RF gain!
NB, DNR, Notch Filters IF Shift, and others are used only when when needed. I suspect a newer op will reach for them more often than a more experienced op who will just engage the ear filters.
The RF gain control was long under appreciated by myself, along with RF preamp and attenuator. Proper use of these controls is essential to get NB, DNR, notch, or IF Shift to respond effectively. Limiting the level of the offending noise or signal is necessary to cut the remainder as much as possible when using the feature controls.
This is why I keep radios for a long time as it takes time to learn how well each control works under various conditions.
Just keep playing and you'll find a combination that works for you.