I'm not overly panicked about the 5 on 5 play at this point.
Game 1 - Oilers opened up with 3 straight 5 on 5,, then blew it open by scoring on the PP to make it 4-0. LA then presses because they are down so much and get a couple fortunate ones to make it 4-2, but Edmonton reopens the four goal lead by taking advantage of the PPs. Then LA gets two even more fortunate bounces.
Edmonton ultimately ends up -1 at 5 on 5, but the 5 on 5 got them into a position to win the game in the first place making LA chase and then they window dressed it by pumping three PP goals while LA got some bounces. (3 GF)
Game 2 - LA starts hard and skates out to an early 3-1 lead, all at 5 on 5. Edmonton closes the gap on a PP goal, but ultimately twice erased LA leads with even strength goals. LA ultimately comes out plus 2 in this game and were the better 5 on 5 team, but were also assisted by some poor goaltending, and it wasn't like Edmonton couldn't accomplish anything 5 on 5 (3 GF)
Game 3 - Edmonton skates to a 2-0 lead with two 5 on 5 goals, then adds to it late in the first with a PP goal. LA gets one back in the second but Edmonton quickly gets it back restoring the lead with another 5 on 5 goal. They add some window dressing by scoring 2 PP goals in the third when LA goes full sideshow. Ultimately though, that game was owned by Edmonton 5 on 5. (3GF)
Game 4 - Looks terrible by shot metrics at 5 on 5, but ultimately they never allowed a single goal against and some models were suggesting that despite the volume of shots, LA never really had an amazing scoring chance, just some decent ones. (0 GF)
It all adds up to the teams being -1 at 5 on 5, but really most of LAs 5 on 5 success came on some very lucky bounces and bad goals in Games 1 and 2. After Edmonton cleaned that up for Games 3 and 4, they only managed 1 goal in 2 games.
I'm not overly panicked yet. Only Corsi numbers make Edmonton look poor at 5 on 5 and I suspect there's tons of score effect involved there as LAs been chasing the game all series having been trailing for 134 minutes of play in this series, trailing by 2 or more for 95 minutes of play and trailing by 3 or more goals for 68 minutes.