From memory, even when Eriksen was benched, Conte retained the 3-4-1-2 playing Barella and others in the hole. Presumably in anticipation of fitting Eriksen in the future. In retrospect that formation didn’t work out for us at all and Conte eventually aborted it.
Barella started playing in the hole only this season. Last season it was Brozovic against Roma, his worst game ever since Spalletti changed his position, and then it was Valero for the rest of the reason.
The thing i hate the most on this forum is people getting sorted into sides, us vs. them. I only belong at the side of Inter. But if i have to belong at one side i guess i am team Eriksen.
Back to the topic, in hindsight Conte's biggest mistake was he immmediately dismissed the idea of Eriksen playing as a mezzala in a midfield trio. We wasted a year because of it. But i can understand it. I can understand his decision to switch to a system with a trequartista in order to accomodate Eriksen when he first joined Inter. My issues with Conte are:
1) He didn't waste any time to bench him for 35 year old Borja Valero in a period the team basically had nothing to play for. We were basically out of the scudetto race after the loss in Turin, top 4 was more or les secured and at a time Eriksen needed consistent playing time in order to adjust to a new league, a new team and a new system he was benched by a veteran who was expected to leave at the end of the season.
2) Thankfully he eventually realised the 3-4-1-2 was dysfunctional and he switched back to 3-5-2 (funnily enough Bergamo is always the place where Conte comes to his senses) which gave us a good run of games till the EL final. But instead of sticking with it and working with Eriksen in order to adjust to a mezzala role he switched back to a 3-4-1-2 in 2020/21 preseason for reasons only he knows that led us to a very poor start of a season with Barella the only player to give decent performances in the "1"(Eriksen, Sensi and Vidal were also used unsuccessfully in the trequartista role).
Thankfully Suning situation saved us from ourselves, Eriksen ended up staying and coach and player worked to find a compromise which was the best option for Inter. At the end of the day that's the only thing that matters, the good of Inter. Not Conte. Not Eriksen. Inter.
Now we can finally enjoy a fully functioning midfield so it's time to move on from this saga.