I have been trying to get my partner into Pathfinder 2nd edition, and they do seem taken with it, however he's been having some issues lately with PF2E. Notably, online. The more he gets into PF2E, the more hate he sees for 5E. He's been playing 5E for years now and has invested a lot of time and love into the game, and to see it bad-mouthed online by a ton of people either because they think PF2E is better, or they don't like the system, or because of the company that manages it, has been disheartening to him as of late.
He told me today that he might just stop playing altogether after he's finished with his games because of the hate he's been seeing online, and I would hate for him to drop something he loves and has invested so much time into because of some online hate comments coming from another community in an act of internet tribalism.
I tried telling him that people disliked D&D4E when it came out for various reasons, yet people still play it today, and that when I started playing 5E, 4E had the reputation of being the game that everyone hates, but he's still focused on how people will bad-mouth 5E when they really have no need to. One example I can remember him seeing (and before I bring it up, I understand Reddit's culture, but the large amount of forum posts are going to be on Reddit, especially for a large and insular hobby like TTRPGs) was on a Reddit thread of someone asking what an analogous spell or ability would be to some spell in 5E and one person commented something to the effect of "well, you could try using this spell/ability, but you won't get the same effect as you would in 5E because 5E is just for auto-win stuff that doesn't have the player trying hard" (moderately paraphrasing, but I think my point is conveyed well here).
Personally, I like PF2E over 5E, but I'll still play both, mostly because most people will play 5E and not want to try and learn a new system, especially if it's one that has a reputation of having exponentially more rules than the one they already know and are comfortable with. Does anyone have any tips for how I can help my partner here?
There isn't one best tabletop RPG system, or one best edition of tabletop RPG system. There's nothing inherently better about using one system over another. The only real difference is your own preference.
Like, Pathfinder, the first one, is a really interesting and robust system. It's great if you know it, but if you don't know it there are a lot of pitfalls and trap feats built in, and it can be hard to make a character that keeps up with the curve if you don't know what you're doing. Kind of reminds me of Magic: the Gathering in that; lots of options that seem good out of context, but aren't really. That's fine for some groups, for others it's a lot of extra headache.
Does D&D 5e treat your characters as being more robust and capable than, say, AD&D 2e? Yes, absolutely. But like, even that is just the default behavior of the system. That factors in, but a competent DM can run a ruthless game in 5e too, it's just a matter of shifting the numbers.
If your partner feels like 5e is too much of a power fantasy for his tastes, I'd recommend trying Dungeon Crawler Classics. You generate a handful of random level 0 characters and take like 4 per player into a dungeon that's an absolute meat grinder for them. They progress, you add new level 0s if you need to, and you keep going. It's a lot of fun watching your shitty little level 0 farmer grow into a fighter or a wizard or something. DCC is an absolutely ruthless system though, so be prepared to lean into it.
On the other hand, there is still plenty of AD&D 2e material out there. Maybe more than 5e, I'm not really sure. It was pretty robust, though, and less forgiving than 5e without being quite as bad as DCC, but your little level 1 wizard with 4 health can still get one-shotted by pretty much anything.
Of course, you can always just tune these systems to do what you want. Want to play 2e but don't feel like figuring out how THAC0 works or ever bothering to calculate it? Great! Don't. Just slot modern AC and hit rolls in. Start AC at 10 and when 2e says to go down, go up instead. Whenever something would make your THAC0 go down, treat that thing as an attack bonus instead. Hey, check it out, we've just stumbled into 3e's Base Attack Bonus system.
Tabletop rule sets aren't a god for you to worship, they're a tool for you to make as flexible as you need it to be. Take the pieces you want, toss the pieces you don't, add your own stuff. That's how any of this stuff got made to begin with, and it's how it progresses.
Want to make 5e more ruthless? Design an injury system and implement it.
But don't just get sad that some people have some milquetoast criticism about the one edition you happen to have stumbled across first. Who cares? Check out some other systems and develop your own opinions and contexts.
I hope your partner sorts it out!