I agree about multibets. Probably at the start of the season it is better to make single bets. And most likely on underdogs because the favorites are overpriced and the profit does not compensate for the risk. At the beginning of the season, the real strength of the teams is unknown, so the results may be random. In this case, choosing an underdog with large odds may turn out to be profitable.
Is it trying their luck like the Leicester fans?
It's actually quite interesting to choose the underdog team in betting. But, for La Liga, i think its a bit worrying. Because the possibility of winning is in the 3 main clubs, Madrid, Atletico and Barcelona
(if their performances remain consistent). Since the 2019/2020 season until the last season, the Top 4 was filled by the three and added by Sevilla. Maybe, if we don't want to bet on Madrid, and want to get a better win if our guess bet is going right, I will choose Sevilla than Espanyol or other underdogs team.
Winning in betting is not easy (if at all real) and it is always only about the distance. It cannot be said that "we need to bet on the underdog in this match and we will make a profit." For example, we bet on an underdog with 9 odds, and we have assessed the situation more correct than the bookmaker, that is, in fact, the underdog will win 8 out of 9 such games and we will be in the black in the long run. But as you understand, this is a long distance, and it is difficult to find so many similar games in one round. Therefore, everyone chooses how to bet on their own.