Lack of focus/concentration is purely because of anhedonia, if one of those tree recover by some amount, it affects other two.
Yes it's slow process but you should find all possible ways to decrease your suffering, for me at beginning I would walk for 5h a day, shower for 30min or take a bath. I was not able to watch youtube or watch a movie/show for long amount of time, only at around 15 months off I was able to watch movie to the end, but there was still anhedonia present and emptyness, I also was not able to understand story completely because of lack of concentration. Around 8-9 months off I was able to listen to music more. At month 8 I was able to force myself to watch short anime episodes of 10min, few times per day after a walk. I would also play very simple word match/crosswords/math games over phone.