Indeed xenos always come off as weak when you see Predators mauling them easily.
Xenos always face off the weakest opponents namely an incompetent company hiring the most cheapskate of cheapskate workers to throw out the trash. Even Weyland Yutani's "elite" dog hounder soldiers still use those cheapo weapons. The pulse rifle's 9mm casings makes me call out what a tiny penis it has. 9mm is a joke in real life.
The xenomorph's lack of reproduction with each other also makes them come off as incredibly weak and the reason why a parasite by itself cannot be considered perfect. Also if our own viruses haven't wiped out the bacteria then it means viruses are quite weak.

Rewatching Alien 1,2,3,4 we can analyze quickly why xenos are considered weak.
1. Truckers with a traitor among them no less
2. Youngsters/Rookies which killed themselves I shit you not. They killed 8+ marines because they panicked and blew themselves up or flamethrowered themselves. Plus an incompetent general or whatever Gorman was. Plus a traitor among them. Plus environmental factors. Plus "No bullets allowed, roflmao". Plus "Lol no calling for backup. Can't orbital strike despite having the nuke at your disposal". By all logic in an open field even with the incompetent marines they should have killed 150+ Aliens because the Aliens could not reproduce anymore soldiers and they needed the hosts alive(supposedly) , that's why we need to call this first iteration of Cameron aliens highly primitive and not canon for them to even withstand a war against the most incompetent of companies. The Company aka Weyland is also parasitic in nature to the Alien franchise and must be killed off.

Weyland would get its ass kicked by the government or a competent company and not another cheapskate like Seegson Synthetics.
Even Stargate's and Dune's factions which are relatively weak compared to Warhammer would completely whip the floor with Weyland. Only in delusional fanfiction would Weyland ever win.