In general, clubs from the Champions League who join the Europa League are not as strong as Liverpool and Leverkusen, but the presence of these clubs can be a threat to them. I only consider Milan, Lens and Galatasaray who can pose a threat, but based on the consistent performances of Liverpool and Leverkusen, the presence of these clubs can improve their quality to go further in the Europa League.
The results depend on the end of the play-off round, after which a new round will begin. The more strong clubs that join the Europa League, the more excitement there will be for the audience when strong teams compete.
It's still very long and in the January transfer window many teams will improve much better so we can't be sure that Liverpool and Leverkusen will succeed in maintaining their performance and we also don't know how strong the other teams will be, what is certain is that the Europa League will always be presents fierce matches and there are surprises, this is also the case this season even though Liverpool and Leverkusen are very favorites.
The Europa League group matches have ended and now we need to look forward to the play offs and which teams will advance to the know out round and we will be able to see the competition and speculation for the teams that will advance further.