Because those who know of better places to do these missions do NOT tell the rest of the forums ,hence only Ceos and Sothis

So, enlighten us and post a few good locations to do these missions(a pair of locations for back and forth missions please)
For Fed rank? OK - I put my last two ranks for the Corvette on by running data missions between Dobrovolskiy Station in LHS 6031 and White Rose & Wylie Dock in Baker. Multiple Fed factions in both systems, the stations are 409ls (Dobrovolskiy), 51ls (White Rose) and 268ls (Wylie) from the entry points. You can also go to Roentgen Prospect if you don't mind the extra time for a planetary landing, it's on the planet that White Rose orbits.
Once allied with the Fed factions you could usually fill your mission limit without needing to relog in 2.4, no idea if 3.0's mission distribution has changed that though because I haven't been over there since the update. Unlike Ceos and Sothis though, they're slap bang in the middle of the bubble so there's always something that needs doing nearby.
Oh Dobrovolskiy and Wylie are outposts, so no large ships. Like I said I haven't checked it since 3.0 but there's no reason why it shouldn't still be fine; it's the close proximity of the two systems and the number of Fed factions that make them useful and none of that will have changed. With the new mission rewards system it would also probably be a good place to farm a load of EFCs etc if a commander was minded to do so.
(I was actually using LHS 6031 as my bulk passenger mission hub back before the nerf, discovering its usefulness for Fed ranking was just a happy accident. It's a binary system and although it takes about ten minutes to fly out to the secondary star (which you
don't need to do for ranking) there are four stations and a surface base all within about 7ls of each other when you get there,
all of which used to give passenger missions to 36 Ophiuchi, Medb
and Mulachi which were all systems with destinations that paid anything up to 45m per mission.