There really isn't a great way to do matching. If you want to try to do it based on levels, well my lvl 79 with 38k power will destroy 90% of 70-80 players who are probably all middling around 20-30k power. Hell I was lvl 75 with 34k power facing off against people lvl 83-85 in SageWB who had less power than me, and even those with upwards of 43k power I was beating fairly handedly. So my alt on S2 alone shows that if you tried to pair by power or by level it's not guaranteed to be perfect. Now my main is on S95 lvl 85 with 55k power. Should I be forced to wait for 2 hours for a match if there aren't anyone near my power level when I do matsuri as I can't always do Matsuri right away as I have class.
From what I could tell on my two characters, my lvl 79 on S2 being 38k power got matched with people with power ranging from about 18k(level 83 at that) to 46k the past 2 Matsuri and it's mostly all one server, I was able to finish both with 5 victories, one without having to revive/change teams. My lvl 85 on S95 with 55k power I typically get matched with people ranging from 35k(lvl 85s as well) to a max of 90k though I haven't seen higher than 63k in awhile. If I don't join Matsuri until an hour or so in, I typically have to wait over a minute to finally get matched and then occasionally it's an even lower level person, I feel bad but it happens sometimes and they are starting late as well probably hoping to avoid someone like me with high power so it's just a risk you have to take.
It's still better than before cross-server Matsuri where on S95 I would be literally forced to face the same 6 people each week, 3 of which were from my own group, to try and get our 5 wins in.
tl;dr
Get better. Even as a free player there is 0 reasons you should be under 35k at lvl 85, make sure to redeem rewards for Threads and Refines, save your coupons for Lucky Board and increase your power and stop looking for Ninjas. If you aren't spending that's what you have to do until you reach a reasonable power level if you actually want to do well. For the most part Battle Power > Ninjas, but even a Cursed Hidan/Minato/Konan team can't beat a team with 6k more power that's played well, as I have constantly beat numerous times in SWB on S2.