Hello,
The matchmaking algorithm is a little more complicated than that.
The system keeps track of your win/loss ratio and uses it to modify your effective level, which is what it uses to compare you to other players' effective levels. This is why you can match players of a higher level than you when you are "facing a weaker opponent" - this means that they have had a streak of losses that has caused their modified effective level to drop to lower than your modified effective level.

Of course, none of this applies if you go over one minute. If you go over the one minute threshold, the gating procedure is discarded, and you match with the next person in the queue that is also over one minute, completely regardless of your wins and losses. Please be warned that you do this at your own risk! Weaker players are very likely to come across a stronger player when doing this!

As for "If I lose a match, next person I face is 80 level with 290k bp!" this is just bad luck. Some players level freeze, and if they do so, they have higher-than-average power for their level, so they will have the advantage in PVP competitions like this that are based on level. Getting such a player is just bad luck on your part and not really a flaw in the system. The system does not consider their power; only their level.

As for, "How is there nobody, absolutely nobody doing this event that I have to reset my queue 5 times, meaning I wait 5 minutes for just one match which is very time consuming," This is very likely becuase of your relatively low level. There are not as many players that play below your level, so when the system attempts to search for players below your level, if there are no such players, you simply will not get a match.

>>> I face people weaker than me in SWB.

Again, the system is based on level, not power.

I hope this helps clear up much of the misunderstanding around this event! Have a great day!

My apologies, you seemed to be asking about matchmaking. There's no matchmaking in Sage World Battlefields. That's all about clicking.

>>> The problem is, there are lots of players who are weaker than me in my SWB bracket. And the SWB bracket I am in is up to 87(ish) level. There must be at least 100 players if not even more in the server cluster inside that level bracket. Moreover, I am stronger than 90% of those players. The problem is, I only face the 10% that is stronger than me.

I would definitely suggest not clicking on those people!

>>> That is regardless of my W/L history in the current event.
Your W/L history in SWB has no bearing on who you face in your next battle. It's solely based on who you click, or who clicks you! You want to try to be quick and click someone you think you can beat!

>>> However, they still don't answer my question.
Assuming "The question is, whom the weaker 90% matching against while I'm only getting stronger opponents?" is your question, it sounds like you're confusing SWB and Fighting Matsuri Challenge. Fighting Matsuri Challenge is the one where you have to try to win five battles with a team of 4 ninjas that you put together from a bank of 9 ninjas plus your main. If any of your ninjas die, they're out, though you can revive them a limited number of times. Sage World Battlefield is a PVP arena where you choose your premade team and fight other players in a battle royale as quickly as possible to amass points. Too many losses will kick you out of the battlefield, but you don't lose the ninjas if you are defeated. Instead, you gain a stacking damage buff.

So if you're asking about Fighting Matsuri Challenge, the answer is that at this stage in the game, at your power level, there simply may not be that many players below your power level that are playing the event. I know that in many server clusters people below a certain power threshold simply won't do PVP events because they expect nothing but straight losses, so it's quite possible that while people below your power level exist, they aren't playing the event.

And if you're asking about Sage World Battlefields, that's entirely up to you! You have to go find them!