He took over halfway through that season, so half of the blame for that needs to go on Tuchel. Poch did make Spurs into a consistent CL team also and had them competing for the title in several seasons. It's not just getting to a CL final that was impressive. The teams that finished above him in the league on most occasions were spending more money than Spurs.
Btw, your point on Potter or Southgate managing to beat Lille taking over halfway through the season is based on what exactly? Because I doubt many would seriously claim Southgate and Potter are better managers than Tuchel and Poch. In the end PSG only finished 1 point behind Lille.