No!! @tottong has explained that the rift had already started before Conte arrived and besides since Conte arrived he wanted to give Osimhen a chance but because of the rift with the management Conte chose the safe path with Lukaku. Napoli will lose if they don't sell Osimhen this year and therefore they have to lower their price tag but I think it's too late, the Premier League clubs will probably wait until next year, waiting for Osimhen as a free agent. I think this has been planned by Osimhen and his agent because if he really wants to leave as soon as possible then he will also lower his high salary demands.
Conte could not handle conflict between Napoli and Osimhen and he failed to convince Osimhen to stay or Napoli to keep Osimhen at Napoli for the past season. Now with Lukaku and Scudetto last season, Napoli and Conte no longer have reasons to keep Osimhen. It's clear now that their main target is selling Osimhen at as best transfer price as possible in order to have extra money for their club financial budget which can be used for buying new players or player wage in a next season.
Conte proved that he can build up a winning team even Napoli did not have best player resource in Serie A past season. Osimhen is still attractive with many clubs and if he agrees to cut his high salary, he will easily find a next club after leaving Napoli.