Played on Xbox Series X, but it will probably work on all platforms. I you romanced someone in ME1 a small workaround for Paramour II and III would be to reload a save prior to ilos, start the mission and as soon as the climax to the romance finishes you'll get Paramour II, repeat for Paramour III. Now, strangely Paramour II and III will still show up as locked on the ME2 and ME3 extras achievement tracker but will be unlocked in the ME1 tracker and most importantly, your account.
Now, as for the reseting of some cross game achievements (such as 1000 kills) I've noticed that it seems to reset every time you change games, say, if you go from ME2 to ME1 and back to ME2. So the only tip here I have is to stick to a game until you get those achievements.
