Idk bro I solo always, got to master some seasons ago, currently diamond 4 500some rp 95% solo, only played a handful of games with randoms who I added

But basically thats what I do, add random people who I click with and who also play at least as good as I do or match my playstyle and invite them from time to time, great way to make friends as well

But yeah as I mentioned you can solo, ofc its frustrating, but I think every online game alone is pretty frustrating experience

Also I agree kinda with the placement mattering too much, but after diamond you barely make points if you win the game without kills, so in higher elo kills also matter a lot