From the experience without doubt PSG far better than Sociedad because although PSG always be failed to gets the trophy from this competition but they always be as champion favourite for each season PSG even can reach to the final match several years ago so they are obviously more better than Sociedad but i have to says this season PSG performance a bit decline because they have to hard struggle to qualified even PSG position on league standings have to determined on the last match of group stages
In my opinion Sociedad cannot be underestimate because at group stages Sociedad performance was more better compared to PSG and Sociedad can successfully to occupy first place at the end of group stages and the recent performance from both teams is equally same because they are still unbeatable at their domestic league in the last 5 matches and for the first leg PSG will playing as a host and i am sure they will be taking initiative to playing attacking and dominate the game and if PSG can able to beat Sociedad then their journey for second leg will be more easy
Yeah I agree with you that PSG is better based on abilities and experience if the opponent is Real Sociedad I think PSG can still be relied upon. Indeed, Real Sociedad cannot be underestimated especially for their good achievements in Group D compete with Inter Milan and Benfica but in my opinion both teams are at a different level PSG is more suitable when compared to Real Madrid or Barcelona. Besides that, the playing style of the two teams is also different PSG prioritizes pressure in any situation I mean when PSG has the opportunity they will continue to put pressure and that can interfere with the concentration of the opponent, except their opponents Barcelona or Madrid will be different because they have experience in that situation while Real Sociedad has not reached this stage, that is why experience is very necessary in this competition.
As you said PSG will take the opportunity in the first leg scoring and collecting goals as much as possible to be in a safe zone then in the second leg PSG will play without burden and keep pressing. As far as I know Real Sociedad is lacking in attack and pressing so if they conceded first then it would be more difficult for them conversely, if Real Sociedad scored the first goal then that will be an advantage for them because Real Sociedad has a good ability in defense it can be seen from the final results in group D Real Sociedad only conceded 2 goals.