Have a look at either consoles upcoming first party line up and see which you prefer.
Both consoles will have 99% of the same multi platform games regardless.
Sony has a more consistent first party, MS has recently bought a bunch of big named studios which may still not make exclusive games for the next couple of years so keep that into consideration as well.
MS has the Game Pass service which will basically let you play all first party games with a monthly subscription, but games often come and go from the serice and you have no control over what goes on there.
Sony is starting a similar-ish PS "Collections" where they will give you a bunch of the best PS4 games as part of PS+
Multiplayer won't be a big issue because a lot of games are adapting cross play, so you can play with your friends on different devices as well.
Ultimately its up to you to weigh the good and the bad and see which one you think will be better for you.