They are one of the favorites for sure.
Lazio and Athletic Bilbao are two of the strongest teams in the league. Manchester United and Tottenham didn't perform like them. In the end it's still in group stage so don't come to conclusions easily. As long as they advance to quarter final there will be no problem.
All still have a chance and maybe both are one of the favorites because their performance in the competition is still on the right track, but the level of consistency will be a test for everyone because the group stage is only the initial stage for the team before advancing further to the final round. Manchester United, Tottenham are also strong candidates but in terms of team performance, both have declined because they are not consistent. Going through the group stage might give a little picture of how the competition in the European league can be much more interesting for the teams that make it through.
Yes, all teams still have a big chance of getting through the group stage. The system applied this year is a little different, giving small teams the opportunity to move forward and be consistent in facing this competition. Manchester United and Tottenham are the favorite teams who are candidates for champions every season, but After going through several matches, both of them seem to be really declining so that the small teams are getting more enthusiastic and the European league is getting more interesting.
After finishing the preliminary round, which team will enter the semi-finals, we can then determine which team will be the candidate as champion.