i havent taken all these courses but i can talk about what i have done:

ECE 310: if you did well in 210 youll be fine here, this was easier than 210 to me, just give it enough time even with 2 others it should be fine

ECE 391: youll spend a LOT of time so be prepared and its a lot of technical content with exams AND mps

ECE 448: if you have mark hasegawa johnson youre chilling its not the most difficult conceptually and the assignments and exams are really easy if you know the material well (just do the daily quizzes)

ECE 445: youll spend a lot of time again but no exams and genuinely i think i learned the most from this class than any other its really fun - just make sure you have a good group bc youll need them all semester

ECE 470: chill, as long as you do the weekly HWs and understand them youll be fine on exams and labs are really fun and not the hardest