2022 EU GDP was 16.6tn. The UK already has free trade agreements with 7 of the 11 countries in CPTPP and the total trading area only makes up ~<8% of the UK's total trade, so it is doubtful that this can replace the economic damage the divorce from the EU has done. Escpecially if one considers that many of the damages came from worker shortages and supply problems that a pacific trading zone can hardly solve. IF china joins that would, of course, pave the way for massive profits, but also put the whole trading partnership into their hands with them making up half of the total gdp.