Danila Smirnov's comment appears to be correct. E.g. when the TAP pipeline opened, such opinions about its (political) role were mentioned:
On November 14 [2020], the Trans Adriatic Pipeline (TAP) commenced operation. It is difficult to overstate the significance of this development. The new transit link running from Greece’s border with Turkey all the way to Italy, via a 878-km stretch that also crosses Albania and the Adriatic Sea, makes the much-discussed Southern Gas Corridor a reality. It brings an annual 10 billion cubic meters (bcm) of natural gas from the Shah Deniz offshore field in the Caspian to consumers in the EU and the Western Balkans, helps diversify supplies away from Russia, and enhances Azerbaijan’s position on European markets. TAP is also a crucial step for Turkey. Together with the Trans-Anatolian Pipeline (TANAP) and TurkStream, it transforms the country from an importer to a transit route for gas.
TAP is the outcome of a lengthy effort, at both diplomatic and business levels, to deliver Caspian hydrocarbons to the West. It started in the 2000s with the Baku-Tbilisi-Ceyhan (BTC) oil pipeline and the Baku-Tbilisi-Erzurum (BTE) gas pipeline running in parallel. They were an accomplishment for Turkish and U.S. energy diplomacy. The Ukraine gas crises of 2006 and 2009 brought the EU into the mix. Pursuing diversification, the European Commission, alongside several member states, championed Nabucco, an extension of BTE through Turkey and the Balkans. Yet Turkey played its own game and ultimately settled on TANAP, a partnership with Azerbaijan’s SOCAR (the majority shareholder). The last chapter in this saga was written in the summer of 2013. The BP-led Shah Deniz consortium - which at present brings together SOCAR, Turkey’s TPAO, Petronas (Malaysia) and NICO (Iran) - decided in favor of TAP against Nabucco West, a truncated version of the original Nabucco. That was a win for Greece, in the throes of a financial crisis at the time, as well as Italy and a setback for Bulgaria, Romania, Hungary, and Austria. What carried the day was strong business support for TAP: BP (20 percent share), Snam (Italy’s grid operator, 20 percent), Fluxys (19 percent), Enagas (16 percent) and Axpo (5 percent).
[...]
Greece and Bulgaria are clear beneficiaries. DEPA and Bulgargaz have each signed long-term contracts with the Shah Deniz consortium for 1 bcm a year. This volume covers about a quarter of annual demand in Greece and a third in Bulgaria. The ICGB interconnector pipeline under construction between the two neighbors will link up TAP to the Bulgarian gas grid. The Bulgarian government is hopeful that ICGB will be up and running by mid-2021 but chances are this deadline will pass. Bulgaria’s long-term contract with Gazprom, enjoying a virtual monopoly on the market, expires at the end of 2022 and the deal with Shah Deniz provides a bargaining chip in extracting better terms from the Russians. [...]
So TAP is a an alternative of sorts to the defunct Nabucco, with somewhat different backers and destinations, but ultimately enhancing deliveries from Azerbaijan to Europe, and to Bulgaria in particular if/when the ICGB interconnector gets built. (According to Wikipedia, the latter is slated to enter operations in September 2022.)
The [key] differences between Nabucco West and TAP are actually not that easy to ascertain, but it seems to have come down to Azeri state-owned company (SOCAR) preferences for greater exclusivity (100% for TAP for 25 years vs 50% on Nabucco West) from Third Party Access (under EU rules) and their prior investments in Greece.
