I encountered the flash issue in a pogrom with an armored car that spawned trapped in a map corner.
I brought the Cannon to deal with it and a Pickaxe but the Pick didn't really do much to it. Sometimes the Cannon did solid red damage, other times itd flash White.
So im like
(Can armoured cars get stunned?)
In OG xcom grenades are actually OP and I used them just as much as the potent weapons, so ill teach you a lesson here.
It gets you a Very Strong advantage to research Alien Grenades/Sonic Pulsers early on.
In the days before preprimed grenades...
Set your Grenadiers up with one in each hand at loadout.
Id have 2 Grenadiers possibly 3.
The first combat round prime both of them, for each Grenadier (4-6 grenades are ready)
Use the Tank/Coelecanth to scout.
Use Rocket Launcher sniper or Grenadiers to kill
Everything.
It may trigger reaction fire potentially but usually only if you Prime+Throw (75% TU hit)... and as an indirect weapon you can throw it over a hedge and they cant respond.
Send in Autocannon/HE dudes to be on call.
Rifle is one of the most useless weapons in the game. But the Laser Rifle is okay. And the Laser Pistol is just a sidearm for an Autocannon dudes so he doesn't get 'hoist on his own petard. I guess the L.Pistol is kinda like a shotgun for close quarters work but I wont use it past 4 Tiles unless im laser spamming.
There is also the (in)famous Great Grenade Relay that has sorta, but not totally, been shut down in x-piratez. Grenadier tosses one to fellows and they each route that grenade to the soldier who'll actually throw it. However, in Xpiratez the Instant Shot grenades (boom fruits, molotov, BP bomb) are just as convenient - 45-50ish TUs to light and throw isnt too bad.
In X-piratez ive tried the Eurosyndicate route and I find that the hit missions just complicate the game too much. Rebel Generals always seem to get obliterated or ornery about being hard to take down, so his power armor parts are hard to scavenge.
I forget what combos I normally use in past playthroughs (up to version J).
I use Kustom Handcannon alot and a helluva lot of Firebombs.
Also Boom Guns and Adv. Rocket Launcher.
For anti-armor its usually Rail Drivers and I savescum the low damage rolls. Its like, nope my Rail Driver is gonna do its 140 damage.
Lasers are good for putting someone under stun. You give them the Small Launcher pop and then pinprick them with a laser till they collapse.
Early game I figured that out with Holdout Pistols and the Dog Bark. Bonk them and then pinprick until they fall over. They usually dont die.