I don't often RNG rage

[Qiox]

But when I do, it is almost always over Wesnoth.

Such a love hate relationship with this game. Every few years I install it again, play a whole bunch.... then rage quit and uninstall because I become convinced the RNG in this game is broken.

[Ferk]

In the Add-ons there's a Modification called "Better Odds" which might help here.

[Bou]

I won't touch this game again. Too much RNG...ridiculous.

[Ferk]

Obligatory link to the official dev position on this:
https://forums.wesnoth.org/viewtopic.php?t=21317

[Crushmaster]

It can definitely be annoying, but better positioning and recruiting will make you win the vast majority of the time.

[Althis]

There are two add-ons that fix the RNG, because god knows I hate it too!

Aside from those, I would check out the available mods that can help reduce the frustration of playing this game. I like the Free XP mod, which adds XP every time you end a turn.

[The Last Vegan]

There is a difference between 'broken RNG', 'luck', and 'chance'. Wesnoth is chance-dependent just like Risk or TripleA or Call of War are chance-dependent: You roll dice to deal damage. However, the longer a game goes, the closer your 'luck' tends towards ±0%. I certainly have lost to an unlucky death of an experienced unit, or won a game by risking my leader. Yet these are risks both players agree to gamble on, and or rarely the determining factor. Professional Poker players acknowledge 'chance' as a part of the game and bet accordingly. But 'broken RNG' is rarely the determining factor in a Poker game. Even on 1v1 maps, I have had games go on for hours because neither player wanted to take a disadvantageous risk. Each unit has a different upkeep to cost ratio, and damage type, which can lead to powerspikes in the lategame as slow-moving units reach the frontline. When pushing you should always be prepared for contingencies, as the attacker places himself/herself further from his supply line and villages.
Here red makes a 'safe' push: https://www.youtube.com/watch?v=YiD2UOBeh8A&t=564s
And at 1:26 I make an 'unsafe' push on the upper left.
Where 'safe' means it is disadvantageous for your opponent to try killing your units. If you never overextend, then 'chance' will always be in your favour. Of course, your opponent can outmaneouvre you from fog of war or powerspike with a high-damage unit composition during a night/day push. Fall back far enough and you lose villages, just like folding too often in Poker will make you trickle blinds.

tl;dr - If you take risks then you will get punished for bad RNG. If you only take advantageous fights then the better player wins.

Edit - Just had two players ragequit over 'RNG' after suiciding five units, when my luck was 9% below average.