As the government responsible for the whole of Cyprus, the RoC should step in once the current talks between the leaders of the 2 communities fail.
The RoC should put forward a detailed plan for a comprehensive solution on a BBF basis with political equality (similar to Annan), which, however, respects international law and human rights of all RoC citizens (including that of property, free movement etc), has a strong central government and allocates ground on a proportional basis (i.e. the TC-administered region to have 18% of land and 18% of coastline). The solution should of course be in full compliance with EU acquis.
After the 35 years of trying, this should be presented to Turkey as a FINAL chance for a BBF and a timescale should be provided. All parties, including Turkey, the EU, UN etc, should be informed that after a specific dealine this offer by the RoC expires and a BBF is declared unachievable - therefore a return to LEGALITY should be demanded from all parties
i.e. given that Cyprus is now EU-territory, which guarantees the safety and rights of all EU-RoC citizens, including TCs, Turkey should aknowledge there is no longer a justification for exercising its guarantor rights and should therefore remove its troops from Cyprus. Failing to do so should mean the end of all negotiations, the closing of the green line, and use of all legal means to force her to respect legality - including the full blocking of its EU process and a flood of lawsuits at all relevant international courts incl ECHR.