IIRC, these GMRS/FRS "scramblers" are just speech inversion, easily defeated with a simple computer program or electronic box that processes the speech back to normal. Of course, anybody with the same model of radio you have will be able to hear it just as well. True "encryption" is gonna be expensive. I have seen some aftermarket scrambler boards that solder into a standard radio and are programmed with your computer and an adapter cable. These run about $150-200 each and are more secure in that they use a rotating frequency that is synched between the units. Harder to decode, but not impossible. True digital Encryption is pretty secure, but they tend to be in radios that have NSNs and cost about three times the price of a good government issue toilet seat!
Comm security takes many forms, depending on your needs. The speech inversion scramblers are probably "good enough" for most situations. A hardcore scanner hobbyist or a Ham might be able to decode your transmission in real time, certainly an alphabet soup agency will have the equipment. Most others will have no clue what is said. The upgraded aftermarket boards will probably lockout everybody but the alphabet types.
And there is always the old standby of talking in code. "Superman and WonderWoman, meet me at the Batcave. The Green Hornet is loose again! Spiderman out!" Only those in your group would know you just said: "Joe and Karen, meet me at the barn, the cow got loose again! John out!"
Haven't researched satphones recently, but several years ago they were a briefcase with a foldout antenna. Several thousand $ and cost a lot per call. Pretty secure, altho I would assume several radios in Washington are tuned to those things 24/7. IIRC, a major player in the satphone business was losing so much money on it they were gonna crash all their satellites and call it quits until the government stepped in and took it over, seems they used their service and didn't have a viable replacement. Info several years out of date, so things may have changed.