Lazio have only 3 wins in the last 10 games (if you take into account all tournaments) they are on an obvious decline, while Roma in Serie A has a series of 7 wins in a row. The trend of this confrontation is obvious. In the next round Roma plays Juventus, the game will be in Rome. There is a high probability that Roma after the next round will begin to claim Juventus' place. But if Roma lose points, Lazio and Fiorentina will be ready to take advantage.
I almost forgot that Lazio is one of the top clubs in Serie A. But in fact, Lazio's performance has been declining especially since the middle of the season. Only in the UEFA Europa League can this club's performance be quite good and currently they are in the Quarter-finals. While in Serie A? With 2x more attack statistics, even the number of goals is the same as Torino.If we look at the match statistics, the Home and Away results show that Lazio has experienced more wins in Away matches, in fact they have won more.
and this is for the whole season chart and progress and results of SS Lazio this season.
Source: SS Lazio match stats
I think it would be an exaggeration to call Lazio a top club. They are close but no, there is the big four and there are all the rest, even if one of the big four collapses (like Milan this season or Napoli before) it does not change the status.
By the way, Lazio have games with Atalanta and Roma ahead (with a break for Bodo-Glimt in the LE), these could be critical games that will determine their place (including participation in European cups).